CVE-2021-26858 (GCVE-0-2021-26858)
Vulnerability from cvelistv5 – Published: 2021-03-02 23:55 – Updated: 2026-10-01 20:12Title
Microsoft Exchange Server Remote Code Execution Vulnerability
Summary
Microsoft Exchange Server Remote Code Execution Vulnerability
Severity
SSVC
Exploitation: active
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-12 03:55 UTC
CWE
- Remote Code Execution
- CWE-noinfo Not enough information
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://msrc.microsoft.com/update-guide/vulnerabi… | vendor-advisorypatch |
| https://portal.msrc.microsoft.com/en-US/security-… | x_refsource_MISCx_transferred |
| https://www.cisa.gov/known-exploited-vulnerabilit… | government-resource |
Impacted products
24 products
Date Public
2021-03-02 16:00
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: add225a6-d7cb-4f81-b624-c8cdac2f23a5
Exploited: Yes
Timestamps
First Seen: 2021-11-03
Asserted: 2021-11-03
Scope
Notes: Microsoft Exchange Server Remote Code Execution Vulnerability | Affected: Microsoft / Exchange Server | Description: Microsoft Exchange Server contains an unspecified vulnerability that allows for remote code execution. This vulnerability is part of the ProxyLogon exploit chain. | Required action: Apply updates per vendor instructions. | Due date: 2022-05-03 | Known ransomware campaign use (KEV): Known | Notes (KEV): Reference CISA's ED 21-02 (https://www.cisa.gov/news-events/directives/ed-21-02-mitigate-microsoft-exchange-premises-product-vulnerabilities) for further guidance and requirements. Note: The due date for addressing this vulnerability aligns with the requirements outlined in ED 21-02. https://nvd.nist.gov/vuln/detail/CVE-2021-26858
Evidence
Type: Vendor Report
Signal: Successful Exploitation
Confidence: 80%
Source: cisa-kev
Details
| Cwes | |
|---|---|
| Feed | CISA Known Exploited Vulnerabilities Catalog |
| Product | Exchange Server |
| Due Date | 2022-05-03 |
| Date Added | 2021-11-03 |
| Vendorproject | Microsoft |
| Vulnerabilityname | Microsoft Exchange Server Remote Code Execution Vulnerability |
| Knownransomwarecampaignuse | Known |
References
Created: 2026-10-02 08:10 CEST
| Updated: 2026-10-02 08:10 CEST
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
KEV entry ID: 5ed3e0b6-e78f-47ec-8880-82a7e1ff531e
Exploited: Yes
Timestamps
First Seen: 2021-11-03
Asserted: 2021-11-03
Scope
Notes: Microsoft Exchange Server Remote Code Execution Vulnerability | Affected: Microsoft / Microsoft Exchange Server 2013 Cumulative Update 21, Microsoft Exchange Server 2013 Cumulative Update 22, Microsoft Exchange Server 2013 Cumulative Update 23, Microsoft Exchange Server 2016 Cumulative Update 10, Microsoft Exchange Server 2016 Cumulative Update 11, Microsoft Exchange Server 2016 Cumulative Update 12, Microsoft Exchange Server 2016 Cumulative Update 13, Microsoft Exchange Server 2016 Cumulative Update 14, Microsoft Exchange Server 2016 Cumulative Update 15, Microsoft Exchange Server 2016 Cumulative Update 16, Microsoft Exchange Server 2016 Cumulative Update 17, Microsoft Exchange Server 2016 Cumulative Update 18, Microsoft Exchange Server 2016 Cumulative Update 19, Microsoft Exchange Server 2016 Cumulative Update 8, Microsoft Exchange Server 2016 Cumulative Update 9, Microsoft Exchange Server 2019, Microsoft Exchange Server 2019 Cumulative Update 1, Microsoft Exchange Server 2019 Cumulative Update 2, Microsoft Exchange Server 2019 Cumulative Update 3, Microsoft Exchange Server 2019 Cumulative Update 4, Microsoft Exchange Server 2019 Cumulative Update 5, Microsoft Exchange Server 2019 Cumulative Update 6, Microsoft Exchange Server 2019 Cumulative Update 7, Microsoft Exchange Server 2019 Cumulative Update 8 | CVSS: 7.8 (HIGH) | EPSS: 0.93651 | Used in malware: yes | Not yet in CISA KEV: False
Evidence
Type: Public Report
Signal: Confirmed Compromise
Confidence: 70%
Source: previdian
Details
| Feed | Previdian (previdian.com) |
|---|---|
| Title | Microsoft Exchange Server Remote Code Execution Vulnerability |
| Cve Id | CVE-2021-26858 |
| Vendor | Microsoft |
| Ghsa Id | GHSA-R4WP-245Q-VR5W |
| Product | Microsoft Exchange Server 2013 Cumulative Update 21, Microsoft Exchange Server 2013 Cumulative Update 22, Microsoft Exchange Server 2013 Cumulative Update 23, Microsoft Exchange Server 2016 Cumulative Update 10, Microsoft Exchange Server 2016 Cumulative Update 11, Microsoft Exchange Server 2016 Cumulative Update 12, Microsoft Exchange Server 2016 Cumulative Update 13, Microsoft Exchange Server 2016 Cumulative Update 14, Microsoft Exchange Server 2016 Cumulative Update 15, Microsoft Exchange Server 2016 Cumulative Update 16, Microsoft Exchange Server 2016 Cumulative Update 17, Microsoft Exchange Server 2016 Cumulative Update 18, Microsoft Exchange Server 2016 Cumulative Update 19, Microsoft Exchange Server 2016 Cumulative Update 8, Microsoft Exchange Server 2016 Cumulative Update 9, Microsoft Exchange Server 2019, Microsoft Exchange Server 2019 Cumulative Update 1, Microsoft Exchange Server 2019 Cumulative Update 2, Microsoft Exchange Server 2019 Cumulative Update 3, Microsoft Exchange Server 2019 Cumulative Update 4, Microsoft Exchange Server 2019 Cumulative Update 5, Microsoft Exchange Server 2019 Cumulative Update 6, Microsoft Exchange Server 2019 Cumulative Update 7, Microsoft Exchange Server 2019 Cumulative Update 8 |
| Added Date | 2021-11-03T00:00:00.000Z |
| Cvss Score | 7.8 |
| Epss Score | 0.93651 |
| Previous Ids | |
| Cvss Severity | HIGH |
| Virtual Patch | False |
| Cvss Estimated | False |
| Epss Percentile | 0.99841 |
| Used In Malware | yes |
| Vulnerability Id | CVE-2021-26858 |
| Ahead Of Cisa Kev | None |
| Not Yet In Cisa Kev | False |
References
Created: 2026-10-02 09:10 CEST
| Updated: 2026-10-02 09:10 CEST
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-03T20:33:41.156Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26858"
}
],
"title": "CVE Program Container"
},
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2021-26858",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-12T03:55:36.937537Z",
"version": "2.0.3"
},
"type": "ssvc"
}
},
{
"other": {
"content": {
"dateAdded": "2021-11-03",
"reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26858"
},
"type": "kev"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "CWE-noinfo Not enough information",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-10-01T20:12:19.501Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"government-resource"
],
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26858"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2013 Cumulative Update 21",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.00.1395.012",
"status": "affected",
"version": "15.00.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2013 Cumulative Update 22",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.00.1473.006",
"status": "affected",
"version": "15.00.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2013 Cumulative Update 23",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.00.1497.012",
"status": "affected",
"version": "15.00.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 10",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1531.012",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 11",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1591.018",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 12",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1713.010",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 13",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1779.008",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 14",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1847.012",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 15",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1913.012",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 16",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1979.008",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 17",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.2044.013",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 18",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.2106.013",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 19",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.2176.009",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 8",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1415.010",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 9",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1466.016",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0221.018",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1979.006",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0397.011",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 3",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0464.015",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 4",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0659.012",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 5",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0595.008",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 6",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0529.013",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 7",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0721.013",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 8",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0792.010",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:*:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0221.018",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_22:*:*:*:*:*:*",
"versionEndExcluding": "15.00.1473.006",
"versionStartIncluding": "15.00.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_2:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0397.011",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_13:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1779.008",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_23:*:*:*:*:*:*",
"versionEndExcluding": "15.00.1497.012",
"versionStartIncluding": "15.00.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_3:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0464.015",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_14:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1847.012",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_4:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0659.012",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_15:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1913.012",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_5:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0595.008",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_6:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0529.013",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_16:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1979.008",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_17:*:*:*:*:*:*",
"versionEndExcluding": "15.01.2044.013",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_7:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0721.013",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_18:*:*:*:*:*:*",
"versionEndExcluding": "15.01.2106.013",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_19:*:*:*:*:*:*",
"versionEndExcluding": "15.01.2176.009",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_8:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0792.010",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_21:*:*:*:*:*:*",
"versionEndExcluding": "15.00.1395.012",
"versionStartIncluding": "15.00.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_12:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1713.010",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_8:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1415.010",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_1:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1979.006",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_9:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1466.016",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_10:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1531.012",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_11:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1591.018",
"versionStartIncluding": "15.01.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"datePublic": "2021-03-02T16:00:00.000Z",
"descriptions": [
{
"lang": "en-US",
"value": "Microsoft Exchange Server Remote Code Execution Vulnerability"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en-US",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "Remote Code Execution",
"lang": "en-US",
"type": "Impact"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:30:16.317Z",
"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"shortName": "microsoft"
},
"references": [
{
"name": "Microsoft Exchange Server Remote Code Execution Vulnerability",
"tags": [
"vendor-advisory",
"patch"
],
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26858"
}
],
"title": "Microsoft Exchange Server Remote Code Execution Vulnerability"
}
},
"cveMetadata": {
"assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"assignerShortName": "microsoft",
"cveId": "CVE-2021-26858",
"datePublished": "2021-03-02T23:55:27.000Z",
"dateReserved": "2021-02-08T00:00:00.000Z",
"dateUpdated": "2026-10-01T20:12:19.501Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2021-26858",
"date": "2026-10-01",
"epss": "0.93651",
"percentile": "0.99841"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2013 Cumulative Update 21",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.00.1395.012",
"status": "affected",
"version": "15.00.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2013 Cumulative Update 22",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.00.1473.006",
"status": "affected",
"version": "15.00.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2013 Cumulative Update 23",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.00.1497.012",
"status": "affected",
"version": "15.00.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 10",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1531.012",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 11",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1591.018",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 12",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1713.010",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 13",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1779.008",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 14",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1847.012",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 15",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1913.012",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 16",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1979.008",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 17",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.2044.013",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 18",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.2106.013",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 19",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.2176.009",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 8",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1415.010",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 9",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1466.016",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0221.018",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1979.006",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0397.011",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 3",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0464.015",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 4",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0659.012",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 5",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0595.008",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 6",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0529.013",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 7",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0721.013",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 8",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0792.010",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
}
],
"source": "secure@microsoft.com"
}
],
"cisaActionDue": "2022-05-03",
"cisaExploitAdd": "2021-11-03",
"cisaRequiredAction": "Apply updates per vendor instructions.",
"cisaVulnerabilityName": "Microsoft Exchange Server Remote Code Execution Vulnerability",
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_21:*:*:*:*:*:*",
"matchCriteriaId": "B560F8FD-068E-4A16-A37F-A62DCE88FCF2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_22:*:*:*:*:*:*",
"matchCriteriaId": "751FD35F-2ECD-4B75-9589-988CC6AD3058",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2013:cumulative_update_23:*:*:*:*:*:*",
"matchCriteriaId": "DA166F2A-D83B-4D50-AD0B-668D813E0585",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_10:*:*:*:*:*:*",
"matchCriteriaId": "63E362CB-CF75-4B7E-A4B1-D6D84AFCBB68",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_11:*:*:*:*:*:*",
"matchCriteriaId": "9BE04790-85A2-4078-88CE-1787BC5172E7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_12:*:*:*:*:*:*",
"matchCriteriaId": "CCF101BE-27FD-4E2D-A694-C606BD3D1ED7",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_13:*:*:*:*:*:*",
"matchCriteriaId": "4DF5BDB5-205D-4B64-A49A-0152AFCF4A13",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_14:*:*:*:*:*:*",
"matchCriteriaId": "55284CF7-0D04-4216-83FE-4B1F9CA94207",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_15:*:*:*:*:*:*",
"matchCriteriaId": "CA2CE223-AA49-49E6-AC32-59270EFF55AD",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_16:*:*:*:*:*:*",
"matchCriteriaId": "4830D6A9-AF74-480C-8F69-8648CD619980",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_17:*:*:*:*:*:*",
"matchCriteriaId": "079E1E3F-FF25-4B0D-AC98-191D6455A014",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_18:*:*:*:*:*:*",
"matchCriteriaId": "29805EC7-6403-44B9-91EC-109C087E98EB",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_19:*:*:*:*:*:*",
"matchCriteriaId": "28FCA0E8-7D27-4746-9731-91B834CA3E64",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_8:*:*:*:*:*:*",
"matchCriteriaId": "075E907F-AF2F-4C31-86C7-51972BE412A1",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_9:*:*:*:*:*:*",
"matchCriteriaId": "69AF19DC-3D65-49A8-A85F-511085CDF27B",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2019:-:*:*:*:*:*:*",
"matchCriteriaId": "40D8A6DB-9225-4A3F-AD76-192F6CCCF002",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_1:*:*:*:*:*:*",
"matchCriteriaId": "051DE6C4-7456-4C42-BC51-253208AADB4E",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_2:*:*:*:*:*:*",
"matchCriteriaId": "EE320413-D2C9-4B28-89BF-361B44A3F0FF",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_3:*:*:*:*:*:*",
"matchCriteriaId": "104F96DC-E280-4E0A-8586-B043B55888C2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_4:*:*:*:*:*:*",
"matchCriteriaId": "73B3B3FE-7E85-4B86-A983-2C410FFEF4B8",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_5:*:*:*:*:*:*",
"matchCriteriaId": "8A9FB275-7F17-48B2-B528-BE89309D2AF5",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_6:*:*:*:*:*:*",
"matchCriteriaId": "D4AB3C25-CEA8-4D66-AEE4-953C8B17911A",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_7:*:*:*:*:*:*",
"matchCriteriaId": "36CE5C6D-9A04-41F5-AE7C-265779833649",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_8:*:*:*:*:*:*",
"matchCriteriaId": "44ECF39A-1DE1-4870-A494-06A53494338D",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "Microsoft Exchange Server Remote Code Execution Vulnerability"
},
{
"lang": "es",
"value": "Una Vulnerabilidad de Ejecuci\u00f3n de c\u00f3digo remota de Microsoft Exchange Server. Este ID de CVE es diferente de CVE-2021-26412, CVE-2021-26854, CVE-2021-26855, CVE-2021-26857, CVE-2021-27065, CVE-2021-27078"
}
],
"id": "CVE-2021-26858",
"lastModified": "2026-10-01T21:17:16.777",
"metrics": {
"cvssMetricV2": [
{
"acInsufInfo": false,
"baseSeverity": "MEDIUM",
"cvssData": {
"accessComplexity": "MEDIUM",
"accessVector": "NETWORK",
"authentication": "NONE",
"availabilityImpact": "PARTIAL",
"baseScore": 6.8,
"confidentialityImpact": "PARTIAL",
"integrityImpact": "PARTIAL",
"vectorString": "AV:N/AC:M/Au:N/C:P/I:P/A:P",
"version": "2.0"
},
"exploitabilityScore": 8.6,
"impactScore": 6.4,
"obtainAllPrivilege": false,
"obtainOtherPrivilege": false,
"obtainUserPrivilege": false,
"source": "nvd@nist.gov",
"type": "Primary",
"userInteractionRequired": true
}
],
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "secure@microsoft.com",
"type": "Secondary"
},
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "nvd@nist.gov",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2021-26858",
"options": [
{
"exploitation": "active"
},
{
"automatable": "yes"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-12T03:55:36.937537Z",
"version": "2.0.3"
}
}
]
},
"published": "2021-03-03T00:15:12.227",
"references": [
{
"source": "secure@microsoft.com",
"tags": [
"Patch",
"Vendor Advisory"
],
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26858"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Patch",
"Vendor Advisory"
],
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26858"
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"tags": [
"US Government Resource"
],
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26858"
}
],
"sourceIdentifier": "secure@microsoft.com",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "NVD-CWE-noinfo"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
},
"vulnrichment": {
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-03T20:33:41.156Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26858"
}
],
"title": "CVE Program Container"
},
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2021-26858",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-08-12T03:55:36.937537Z",
"version": "2.0.3"
},
"type": "ssvc"
}
},
{
"other": {
"content": {
"dateAdded": "2021-11-03",
"reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26858"
},
"type": "kev"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "CWE-noinfo Not enough information",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2025-02-04T19:16:27.554Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"government-resource"
],
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26858"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2013 Cumulative Update 21",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.00.1395.012",
"status": "affected",
"version": "15.00.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2013 Cumulative Update 22",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.00.1473.006",
"status": "affected",
"version": "15.00.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2013 Cumulative Update 23",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.00.1497.012",
"status": "affected",
"version": "15.00.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 10",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1531.012",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 11",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1591.018",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 12",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1713.010",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 13",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1779.008",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 14",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1847.012",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 15",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1913.012",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 16",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1979.008",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 17",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.2044.013",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 18",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.2106.013",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 19",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.2176.009",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 8",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1415.010",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2016 Cumulative Update 9",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1466.016",
"status": "affected",
"version": "15.01.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0221.018",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 1",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.01.1979.006",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 2",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0397.011",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 3",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0464.015",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 4",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0659.012",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 5",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0595.008",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 6",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0529.013",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 7",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0721.013",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
},
{
"platforms": [
"x64-based Systems"
],
"product": "Microsoft Exchange Server 2019 Cumulative Update 8",
"vendor": "Microsoft",
"versions": [
{
"lessThan": "15.02.0792.010",
"status": "affected",
"version": "15.02.0",
"versionType": "custom"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:*:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0221.018",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_22:*:*:*:*:*:*",
"versionEndExcluding": "15.00.1473.006",
"versionStartIncluding": "15.00.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_2:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0397.011",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_13:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1779.008",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_23:*:*:*:*:*:*",
"versionEndExcluding": "15.00.1497.012",
"versionStartIncluding": "15.00.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_3:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0464.015",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_14:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1847.012",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_4:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0659.012",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_15:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1913.012",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_5:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0595.008",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_6:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0529.013",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_16:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1979.008",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_17:*:*:*:*:*:*",
"versionEndExcluding": "15.01.2044.013",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_7:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0721.013",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_18:*:*:*:*:*:*",
"versionEndExcluding": "15.01.2106.013",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_19:*:*:*:*:*:*",
"versionEndExcluding": "15.01.2176.009",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_8:*:*:*:*:*:*",
"versionEndExcluding": "15.02.0792.010",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_21:*:*:*:*:*:*",
"versionEndExcluding": "15.00.1395.012",
"versionStartIncluding": "15.00.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_12:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1713.010",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_8:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1415.010",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_1:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1979.006",
"versionStartIncluding": "15.02.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_9:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1466.016",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_10:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1531.012",
"versionStartIncluding": "15.01.0",
"vulnerable": true
},
{
"criteria": "cpe:2.3:a:microsoft:exchange_server:*:cumulative_update_11:*:*:*:*:*:*",
"versionEndExcluding": "15.01.1591.018",
"versionStartIncluding": "15.01.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"datePublic": "2021-03-02T16:00:00.000Z",
"descriptions": [
{
"lang": "en-US",
"value": "Microsoft Exchange Server Remote Code Execution Vulnerability"
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C",
"version": "3.1"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en-US",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "Remote Code Execution",
"lang": "en-US",
"type": "Impact"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:30:16.317Z",
"orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"shortName": "microsoft"
},
"references": [
{
"name": "Microsoft Exchange Server Remote Code Execution Vulnerability",
"tags": [
"vendor-advisory",
"patch"
],
"url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-26858"
}
],
"title": "Microsoft Exchange Server Remote Code Execution Vulnerability"
}
},
"cveMetadata": {
"assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
"assignerShortName": "microsoft",
"cveId": "CVE-2021-26858",
"datePublished": "2021-03-02T23:55:27.000Z",
"dateReserved": "2021-02-08T00:00:00.000Z",
"dateUpdated": "2026-10-01T20:12:19.501Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Loading…
Loading…
The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…