Vulnerability-Lookup

MSRC_CVE-2026-78512

Vulnerability from csaf_microsoft - Published: 2026-09-08 07:00 - Updated: 2026-09-17 07:00

Summary

Microsoft Office Word Remote Code Execution Vulnerability

Notes

Additional Resources: To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle

Disclaimer: The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.

CVE-2026-78512

8.8 (High)


                
                  CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

CWE-197 - Numeric Truncation Error

Affected products

Fixed 13 products

Product	Identifier	Version	Remediation
Microsoft Office 2019 for 32-bit editions 16.0.10417.20207 Microsoft / Microsoft Office 2019 for 32-bit editions		16.0.10417.20207
Microsoft Office 2019 for 64-bit editions 16.0.10417.20207 Microsoft / Microsoft Office 2019 for 64-bit editions		16.0.10417.20207
Microsoft 365 Apps for Enterprise for 32-bit Systems 16.0.20326.20138 Microsoft / Microsoft 365 Apps for Enterprise for 32-bit Systems		16.0.20326.20138
Microsoft 365 Apps for Enterprise for 64-bit Systems 16.0.20326.20138 Microsoft / Microsoft 365 Apps for Enterprise for 64-bit Systems		16.0.20326.20138
Microsoft Office LTSC for Mac 2021 16.113.26091433 Microsoft / Microsoft Office LTSC for Mac 2021		16.113.26091433
Microsoft Office LTSC 2021 for 64-bit editions 16.0.14334.20906 Microsoft / Microsoft Office LTSC 2021 for 64-bit editions		16.0.14334.20906
Microsoft Office LTSC 2021 for 32-bit editions 16.0.14334.20906 Microsoft / Microsoft Office LTSC 2021 for 32-bit editions		16.0.14334.20906
Microsoft Office LTSC 2024 for 32-bit editions 16.0.17932.20976 Microsoft / Microsoft Office LTSC 2024 for 32-bit editions		16.0.17932.20976
Microsoft Office LTSC 2024 for 64-bit editions 16.0.17932.20976 Microsoft / Microsoft Office LTSC 2024 for 64-bit editions		16.0.17932.20976
Microsoft Office LTSC for Mac 2024 16.113.26091433 Microsoft / Microsoft Office LTSC for Mac 2024		16.113.26091433
Microsoft Office 2016 (32-bit edition) 16.0.5569.1002 Microsoft / Microsoft Office 2016 (32-bit edition)		16.0.5569.1002
Microsoft Office 2016 (64-bit edition) 16.0.5569.1002 Microsoft / Microsoft Office 2016 (64-bit edition)		16.0.5569.1002
Microsoft Office 365 for Mac 16.113.26091433 Microsoft / Microsoft Office 365 for Mac		16.113.26091433

Known affected 13 products

Product	Version	Remediation
Microsoft Office 2019 for 32-bit editions <16.0.10417.20207 Microsoft / Microsoft Office 2019 for 32-bit editions	<16.0.10417.20207	Vendor Fix fix
Microsoft Office 2019 for 64-bit editions <16.0.10417.20207 Microsoft / Microsoft Office 2019 for 64-bit editions	<16.0.10417.20207	Vendor Fix fix
Microsoft 365 Apps for Enterprise for 32-bit Systems <16.0.20326.20138 Microsoft / Microsoft 365 Apps for Enterprise for 32-bit Systems	<16.0.20326.20138	Vendor Fix fix
Microsoft 365 Apps for Enterprise for 64-bit Systems <16.0.20326.20138 Microsoft / Microsoft 365 Apps for Enterprise for 64-bit Systems	<16.0.20326.20138	Vendor Fix fix
Microsoft Office LTSC for Mac 2021 <16.113.26091433 Microsoft / Microsoft Office LTSC for Mac 2021	<16.113.26091433	Vendor Fix fix
Microsoft Office LTSC 2021 for 64-bit editions <16.0.14334.20906 Microsoft / Microsoft Office LTSC 2021 for 64-bit editions	<16.0.14334.20906	Vendor Fix fix
Microsoft Office LTSC 2021 for 32-bit editions <16.0.14334.20906 Microsoft / Microsoft Office LTSC 2021 for 32-bit editions	<16.0.14334.20906	Vendor Fix fix
Microsoft Office LTSC 2024 for 32-bit editions <16.0.17932.20976 Microsoft / Microsoft Office LTSC 2024 for 32-bit editions	<16.0.17932.20976	Vendor Fix fix
Microsoft Office LTSC 2024 for 64-bit editions <16.0.17932.20976 Microsoft / Microsoft Office LTSC 2024 for 64-bit editions	<16.0.17932.20976	Vendor Fix fix
Microsoft Office LTSC for Mac 2024 <16.113.26091433 Microsoft / Microsoft Office LTSC for Mac 2024	<16.113.26091433	Vendor Fix fix
Microsoft Office 2016 (32-bit edition) <16.0.5569.1002 Microsoft / Microsoft Office 2016 (32-bit edition)	<16.0.5569.1002	Vendor Fix fix
Microsoft Office 2016 (64-bit edition) <16.0.5569.1002 Microsoft / Microsoft Office 2016 (64-bit edition)	<16.0.5569.1002	Vendor Fix fix
Microsoft Office 365 for Mac <16.113.26091433 Microsoft / Microsoft Office 365 for Mac	<16.113.26091433	Vendor Fix fix

References

4 references

URL	Category
https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self
https://support.microsoft.com/lifecycle	external
https://www.first.org/cvss	external
https://msrc.microsoft.com/csaf/vex/2026/msrc_cve…	self

JSON

To clipboard

{
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    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
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    "notes": [
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        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
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      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2026-78512 Microsoft Office Word Remote Code Execution Vulnerability - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-78512.json"
      },
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    "title": "Microsoft Office Word Remote Code Execution Vulnerability",
    "tracking": {
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      "generator": {
        "date": "2026-10-01T22:52:25.124Z",
        "engine": {
          "name": "MSRC Generator",
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          "summary": "Information published."
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          "date": "2026-09-17T07:00:00.000Z",
          "legacy_version": "2",
          "number": "2",
          "summary": "Microsoft is announcing the availability of the security updates for Microsoft Office for Mac. Customers running affected Mac software should install the update for their product to be protected from this vulnerability. Customers running other Microsoft Office software do not need to take any action. See the [Release Notes](https://go.microsoft.com/fwlink/p/?linkid=831049) for more information and download links."
        }
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  "vulnerabilities": [
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      "cwe": {
        "id": "CWE-197",
        "name": "Numeric Truncation Error"
      },
      "notes": [
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          "text": "Microsoft",
          "title": "Assigning CNA"
        }
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          "10",
          "9",
          "8",
          "7",
          "6",
          "5",
          "4",
          "3",
          "2",
          "13",
          "12",
          "1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2026-78512 Microsoft Office Word Remote Code Execution Vulnerability - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-78512.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2026-09-08T07:00:00.000Z",
          "details": "16.0.10417.20207:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates",
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          "product_ids": [
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            "3"
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          "product_ids": [
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            "12"
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          "url": "https://support.microsoft.com/help/4011160"
        },
        {
          "category": "vendor_fix",
          "date": "2026-09-08T07:00:00.000Z",
          "details": "16.113.26091433:Security Update:https://www.microsoft.com/en-us/microsoft-365/mac/microsoft-365-for-mac?msockid=35f9adb0e74b61392038b90de6fe608c",
          "product_ids": [
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          "url": "https://www.microsoft.com/en-us/microsoft-365/mac/microsoft-365-for-mac?msockid=35f9adb0e74b61392038b90de6fe608c"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "exploitCodeMaturity": "UNPROVEN",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "remediationLevel": "OFFICIAL_FIX",
            "reportConfidence": "CONFIRMED",
            "scope": "UNCHANGED",
            "temporalScore": 7.7,
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C",
            "version": "3.1"
          },
          "products": [
            "1",
            "2",
            "3",
            "4",
            "5",
            "6",
            "7",
            "8",
            "9",
            "10",
            "11",
            "12",
            "13"
          ]
        }
      ],
      "title": "Microsoft Office Word Remote Code Execution Vulnerability"
    }
  ]
}

CVE-2026-78512 (GCVE-0-2026-78512)

Vulnerability from cvelistv5 – Published: 2026-09-08 17:18 – Updated: 2026-10-01 23:00

Title

Microsoft Office Word Remote Code Execution Vulnerability

Summary

Numeric truncation error in Microsoft Office Word allows an unauthorized attacker to execute code over a network.

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-09 04:22 UTC

CWE

CWE-197 - Numeric Truncation Error
CWE-122 - Heap-based Buffer Overflow

Assigner

microsoft mitre root Scorecard

References

1 reference

URL	Tags
https://msrc.microsoft.com/update-guide/vulnerabi…	vendor-advisorypatch

Impacted products

8 products

Vendor	Product	Version
Microsoft	Microsoft 365 Apps for Enterprise	Affected: 16.0.1 , < 16.0.20326.20138 (custom)
Microsoft	Microsoft Office 2016	Affected: 16.0.0 , < 16.0.5569.1002 (custom)
Microsoft	Microsoft Office 2019	Affected: 19.0.0 , < 16.0.10417.20207 (custom)
Microsoft	Microsoft Office 365 for Mac	Affected: 1.0.0 , < 16.113.26091433 (custom)
Microsoft	Microsoft Office LTSC 2021	Affected: 16.0.1 , < 16.0.14334.20906 (custom)
Microsoft	Microsoft Office LTSC 2024	Affected: 16.0.0 , < 16.0.17932.20976 (custom)
Microsoft	Microsoft Office LTSC for Mac 2021	Affected: 16.0.1 , < 16.113.26091433 (custom)
Microsoft	Microsoft Office LTSC for Mac 2024	Affected: 16.0.0 , < 16.113.26091433 (custom)

Date Public

2026-09-08 14:00

Show details on NVD website

JSON

To clipboard

{
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            "other": {
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                "id": "CVE-2026-78512",
                "options": [
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                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-09-09T04:22:37.096728Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-09-09T09:54:50.352Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "platforms": [
            "32-bit Systems",
            "x64-based Systems"
          ],
          "product": "Microsoft 365 Apps for Enterprise",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "16.0.20326.20138",
              "status": "affected",
              "version": "16.0.1",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "32-bit Systems",
            "x64-based Systems"
          ],
          "product": "Microsoft Office 2016",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "16.0.5569.1002",
              "status": "affected",
              "version": "16.0.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "32-bit Systems",
            "x64-based Systems"
          ],
          "product": "Microsoft Office 2019",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "16.0.10417.20207",
              "status": "affected",
              "version": "19.0.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "product": "Microsoft Office 365 for Mac",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "16.113.26091433",
              "status": "affected",
              "version": "1.0.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "32-bit Systems",
            "x64-based Systems"
          ],
          "product": "Microsoft Office LTSC 2021",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "16.0.14334.20906",
              "status": "affected",
              "version": "16.0.1",
              "versionType": "custom"
            }
          ]
        },
        {
          "platforms": [
            "32-bit Systems",
            "x64-based Systems"
          ],
          "product": "Microsoft Office LTSC 2024",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "16.0.17932.20976",
              "status": "affected",
              "version": "16.0.0",
              "versionType": "custom"
            }
          ]
        },
        {
          "product": "Microsoft Office LTSC for Mac 2021",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "16.113.26091433",
              "status": "affected",
              "version": "16.0.1",
              "versionType": "custom"
            }
          ]
        },
        {
          "product": "Microsoft Office LTSC for Mac 2024",
          "vendor": "Microsoft",
          "versions": [
            {
              "lessThan": "16.113.26091433",
              "status": "affected",
              "version": "16.0.0",
              "versionType": "custom"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:a:microsoft:office_2019:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "16.0.10417.20207",
                  "versionStartIncluding": "19.0.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:365_apps:*:*:*:*:enterprise:*:*:*",
                  "versionEndExcluding": "16.0.20326.20138",
                  "versionStartIncluding": "16.0.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:office_macos_2021:*:*:*:*:*:long_term_servicing_channel:*:*",
                  "versionEndExcluding": "16.113.26091433",
                  "versionStartIncluding": "16.0.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:office_2021:*:*:*:*:long_term_servicing_channel:*:*:*",
                  "versionEndExcluding": "16.0.14334.20906",
                  "versionStartIncluding": "16.0.1",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:office_2024:*:*:*:*:long_term_servicing_channel:*:*:*",
                  "versionEndExcluding": "16.0.17932.20976",
                  "versionStartIncluding": "16.0.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:office_macos_2024:*:*:*:*:*:long_term_servicing_channel:*:*",
                  "versionEndExcluding": "16.113.26091433",
                  "versionStartIncluding": "16.0.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:office_2016:*:*:*:*:*:*:x86:*",
                  "versionEndExcluding": "16.0.5569.1002",
                  "versionStartIncluding": "16.0.0",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:a:microsoft:office_365:*:*:*:*:*:macos:*:*",
                  "versionEndExcluding": "16.113.26091433",
                  "versionStartIncluding": "1.0.0",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "datePublic": "2026-09-08T14:00:00.000Z",
      "descriptions": [
        {
          "lang": "en-US",
          "value": "Numeric truncation error in Microsoft Office Word allows an unauthorized attacker to execute code over a network."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C",
            "version": "3.1"
          },
          "format": "CVSS",
          "scenarios": [
            {
              "lang": "en-US",
              "value": "GENERAL"
            }
          ]
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-197",
              "description": "CWE-197: Numeric Truncation Error",
              "lang": "en-US",
              "type": "CWE"
            },
            {
              "cweId": "CWE-122",
              "description": "CWE-122: Heap-based Buffer Overflow",
              "lang": "en-US",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-01T23:00:19.868Z",
        "orgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
        "shortName": "microsoft"
      },
      "references": [
        {
          "name": "Microsoft Office Word Remote Code Execution Vulnerability",
          "tags": [
            "vendor-advisory",
            "patch"
          ],
          "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-78512"
        }
      ],
      "title": "Microsoft Office Word Remote Code Execution Vulnerability"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "f38d906d-7342-40ea-92c1-6c4a2c6478c8",
    "assignerShortName": "microsoft",
    "cveId": "CVE-2026-78512",
    "datePublished": "2026-09-08T17:18:33.310Z",
    "dateReserved": "2026-08-24T17:28:00.622Z",
    "dateUpdated": "2026-10-01T23:00:19.868Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

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.

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.

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.

Action not permitted

MSRC_CVE-2026-78512

CVE-2026-78512 (GCVE-0-2026-78512)

Tags

Sightings

Nomenclature

Related by attack behaviour