CVE-2026-62432 (GCVE-0-2026-62432)
Vulnerability from cvelistv5 – Published: 2026-07-28 12:32 – Updated: 2026-07-28 16:33
VLAI
EPSS
VEX
Title
evtchn: Race between FIFO expand and reset
Summary
The EVTCHNOP_expand_array hypercall checks for whether FIFO event
channels are enabled, but without holding the correct lock. It can race
with EVTCHNOP_reset, resulting in dereferencing a NULL pointer.
Severity
7.3 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-28 15:13 UTC
CWE
- CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Assigner
References
Date Public
2026-07-28 12:00
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2026-07-28T16:33:32.509Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"url": "http://xenbits.xen.org/xsa/advisory-505.html"
},
{
"url": "http://www.openwall.com/lists/oss-security/2026/07/28/21"
}
],
"title": "CVE Program Container"
},
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "LOW",
"baseScore": 7.3,
"baseSeverity": "HIGH",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-62432",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-28T15:13:34.638706Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-362",
"description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (\u0027Race Condition\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-28T15:13:39.575Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unknown",
"product": "Xen",
"vendor": "Xen",
"versions": [
{
"status": "unknown",
"version": "consult Xen advisory XSA-505"
}
]
}
],
"configurations": [
{
"lang": "en",
"value": "All Xen versions from 4.5 onwards are vulnerable. Xen versions 4.4 and\nearlier are not vulnerable."
}
],
"datePublic": "2026-07-28T12:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "The EVTCHNOP_expand_array hypercall checks for whether FIFO event\nchannels are enabled, but without holding the correct lock. It can race\nwith EVTCHNOP_reset, resulting in dereferencing a NULL pointer."
}
],
"impacts": [
{
"descriptions": [
{
"lang": "en",
"value": "A malicious HVM guest (x86 HVM or PVH, and ARM) can crash Xen leading to\na denial of service.\n\nA malicious x86 PV guest can most likely crash Xen leading to a denial\nof service, but memory corruption or privilege escalation cannot be\nruled out."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-28T12:32:52.043Z",
"orgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
"shortName": "XEN"
},
"references": [
{
"url": "https://xenbits.xenproject.org/xsa/advisory-505.html"
}
],
"title": "evtchn: Race between FIFO expand and reset",
"workarounds": [
{
"lang": "en",
"value": "There are no mitigations."
}
]
}
},
"cveMetadata": {
"assignerOrgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
"assignerShortName": "XEN",
"cveId": "CVE-2026-62432",
"datePublished": "2026-07-28T12:32:52.043Z",
"dateReserved": "2026-07-14T10:28:12.655Z",
"dateUpdated": "2026-07-28T16:33:32.509Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-62432",
"date": "2026-10-01",
"epss": "0.00318",
"percentile": "0.22451"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unknown",
"product": "Xen",
"vendor": "Xen",
"versions": [
{
"status": "unknown",
"version": "consult Xen advisory XSA-505"
}
]
}
],
"source": "security@xen.org"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "The EVTCHNOP_expand_array hypercall checks for whether FIFO event\nchannels are enabled, but without holding the correct lock. It can race\nwith EVTCHNOP_reset, resulting in dereferencing a NULL pointer."
}
],
"id": "CVE-2026-62432",
"lastModified": "2026-07-28T17:16:56.733",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "LOW",
"baseScore": 7.3,
"baseSeverity": "HIGH",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 3.4,
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-62432",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-28T15:13:34.638706Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-07-28T13:19:02.110",
"references": [
{
"source": "security@xen.org",
"url": "https://xenbits.xenproject.org/xsa/advisory-505.html"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "http://www.openwall.com/lists/oss-security/2026/07/28/21"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "http://xenbits.xen.org/xsa/advisory-505.html"
}
],
"sourceIdentifier": "security@xen.org",
"vulnStatus": "Deferred",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-362"
}
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
]
}
},
"redhat_vex": {
"current_release_date": "2026-07-28T18:10:46+00:00",
"cve": "CVE-2026-62432",
"id": "CVE-2026-62432",
"initial_release_date": "2026-07-28T12:32:52.043000+00:00",
"product_status:known_not_affected": "1",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "xen: Xen: Race condition in event channel handling can lead to denial of service",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-62432.json",
"version": "3"
},
"vulnrichment": {
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2026-07-28T16:33:32.509Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"url": "http://xenbits.xen.org/xsa/advisory-505.html"
},
{
"url": "http://www.openwall.com/lists/oss-security/2026/07/28/21"
}
],
"title": "CVE Program Container"
},
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "LOW",
"baseScore": 7.3,
"baseSeverity": "HIGH",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2026-62432",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-07-28T15:13:34.638706Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-362",
"description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (\u0027Race Condition\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-28T15:12:12.056Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unknown",
"product": "Xen",
"vendor": "Xen",
"versions": [
{
"status": "unknown",
"version": "consult Xen advisory XSA-505"
}
]
}
],
"configurations": [
{
"lang": "en",
"value": "All Xen versions from 4.5 onwards are vulnerable. Xen versions 4.4 and\nearlier are not vulnerable."
}
],
"datePublic": "2026-07-28T12:00:00.000Z",
"descriptions": [
{
"lang": "en",
"value": "The EVTCHNOP_expand_array hypercall checks for whether FIFO event\nchannels are enabled, but without holding the correct lock. It can race\nwith EVTCHNOP_reset, resulting in dereferencing a NULL pointer."
}
],
"impacts": [
{
"descriptions": [
{
"lang": "en",
"value": "A malicious HVM guest (x86 HVM or PVH, and ARM) can crash Xen leading to\na denial of service.\n\nA malicious x86 PV guest can most likely crash Xen leading to a denial\nof service, but memory corruption or privilege escalation cannot be\nruled out."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-07-28T12:32:52.043Z",
"orgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
"shortName": "XEN"
},
"references": [
{
"url": "https://xenbits.xenproject.org/xsa/advisory-505.html"
}
],
"title": "evtchn: Race between FIFO expand and reset",
"workarounds": [
{
"lang": "en",
"value": "There are no mitigations."
}
]
}
},
"cveMetadata": {
"assignerOrgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
"assignerShortName": "XEN",
"cveId": "CVE-2026-62432",
"datePublished": "2026-07-28T12:32:52.043Z",
"dateReserved": "2026-07-14T10:28:12.655Z",
"dateUpdated": "2026-07-28T16:33:32.509Z",
"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…