Vulnerability-Lookup

CVE-2026-62432 (GCVE-0-2026-62432)

Vulnerability from cvelistv5 – Published: 2026-07-28 12:32 – Updated: 2026-07-28 16:33

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)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

SSVC

Exploitation: none Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Assigner

XEN

References

3 references

URL	Tags
https://xenbits.xenproject.org/xsa/advisory-505.html
http://xenbits.xen.org/xsa/advisory-505.html
http://www.openwall.com/lists/oss-security/2026/0…

Impacted products

1 product

Vendor	Product	Version
Xen	Xen	Unknown: consult Xen advisory XSA-505

Date Public

2026-07-28 12:00

Show details on NVD website

JSON

To clipboard

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  "containers": {
    "adp": [
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        "providerMetadata": {
          "dateUpdated": "2026-07-28T16:33:32.509Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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        "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"
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      {
        "metrics": [
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              "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",
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            }
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            "other": {
              "content": {
                "id": "CVE-2026-62432",
                "options": [
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                    "Exploitation": "none"
                  },
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                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-07-28T15:13:34.638706Z",
                "version": "2.0.3"
              },
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            }
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        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-362",
                "description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (\u0027Race Condition\u0027)",
                "lang": "en",
                "type": "CWE"
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          "dateUpdated": "2026-07-28T15:13:39.575Z",
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        },
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      }
    ],
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          "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."
        }
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      "datePublic": "2026-07-28T12:00:00.000Z",
      "descriptions": [
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          "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": {
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-62432\",\"sourceIdentifier\":\"security@xen.org\",\"published\":\"2026-07-28T13:19:02.110\",\"lastModified\":\"2026-07-28T17:16:56.733\",\"vulnStatus\":\"Deferred\",\"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.\"}],\"affected\":[{\"source\":\"security@xen.org\",\"affectedData\":[{\"vendor\":\"Xen\",\"product\":\"Xen\",\"defaultStatus\":\"unknown\",\"versions\":[{\"version\":\"consult Xen advisory XSA-505\",\"status\":\"unknown\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L\",\"baseScore\":7.3,\"baseSeverity\":\"HIGH\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"LOW\",\"integrityImpact\":\"LOW\",\"availabilityImpact\":\"LOW\"},\"exploitabilityScore\":3.9,\"impactScore\":3.4}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2026-07-28T15:13:34.638706Z\",\"id\":\"CVE-2026-62432\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"yes\"},{\"technicalImpact\":\"partial\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-362\"}]}],\"references\":[{\"url\":\"https://xenbits.xenproject.org/xsa/advisory-505.html\",\"source\":\"security@xen.org\"},{\"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\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"}]}}",
    "redhat_vex": {
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      "cve": "CVE-2026-62432",
      "id": "CVE-2026-62432",
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      "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": {
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}

GHSA-92F9-Q54W-FXM8

Vulnerability from github – Published: 2026-07-28 15:32 – Updated: 2026-07-28 18:33

Details

Severity

7.3 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Show details on source website

JSON

To clipboard

{
  "affected": [],
  "aliases": [
    "CVE-2026-62432"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-362"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-28T13:19:02Z",
    "severity": "HIGH"
  },
  "details": "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": "GHSA-92f9-q54w-fxm8",
  "modified": "2026-07-28T18:33:02Z",
  "published": "2026-07-28T15:32:17Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-62432"
    },
    {
      "type": "WEB",
      "url": "https://xenbits.xenproject.org/xsa/advisory-505.html"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/07/28/21"
    },
    {
      "type": "WEB",
      "url": "http://xenbits.xen.org/xsa/advisory-505.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
      "type": "CVSS_V3"
    }
  ]
}

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.

Detection rules are retrieved from Rulezet.

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.

Action not permitted

CVE-2026-62432 (GCVE-0-2026-62432)

GHSA-92F9-Q54W-FXM8

Tags

Sightings

Nomenclature