CVE-2026-79610 (GCVE-0-2026-79610)

Vulnerability from cvelistv5 – Published: 2026-10-13 15:44 – Updated: 2026-10-13 16:13
VLAI
Title
grant-table: double version change race
Summary
XSA-501 was about issues with v1 -> v2 and v2 -> v1 changes racing certain other grant table operations. Sadly a v2 -> v1 -> v2 change has yet another effect which wasn't accounted for: During the first change, status pages would be freed. During the second change they would be allocated again. Hence across the full pair of change the addresses of the status pages may change, rendering stale previously calculated pointers into the status array.
Severity
No CVSS data available.
Assigner
XEN CNA under the mitre root
CNA scorecard D 56/100 over 46 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Xen Xen Unknown: consult Xen advisory XSA-517
guessed Create a notification for this product.
Date Public
2026-10-13 12:00
Credits
This issue was discovered by Claude Opus and diagnosed as a security issue by Teddy Astie of Vates.
Show details on NVD website
To clipboard 

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          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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            "url": "http://xenbits.xen.org/xsa/advisory-517.html"
          },
          {
            "url": "http://www.openwall.com/lists/oss-security/2026/10/13/6"
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        "title": "CVE Program Container"
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          "defaultStatus": "unknown",
          "product": "Xen",
          "vendor": "Xen",
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          ]
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      ],
      "configurations": [
        {
          "lang": "en",
          "value": "All Xen versions from 4.0 onwards are vulnerable.  Xen versions 3.4 and\nearlier are not vulnerable.\n\nOnly x86 guests permitted to use grant table version 2 interfaces can\nleverage this vulnerability.  On Arm, grant table v2 use is explicitly\nunsupported.\n\nOnly multi-vCPU guests can leverage this vulnerability.\n\nXen versions 4.13 and newer offer a way to build Xen without grant table\nsupport.  Such hypervisors (CONFIG_GRANT_TABLE turned off) are not\nvulnerable."
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "This issue was discovered by Claude Opus and diagnosed as a security issue\nby Teddy Astie of Vates."
        }
      ],
      "datePublic": "2026-10-13T12:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "XSA-501 was about issues with v1 -\u003e v2 and v2 -\u003e v1 changes racing certain\nother grant table operations.  Sadly a v2 -\u003e v1 -\u003e v2 change has yet\nanother effect which wasn\u0027t accounted for: During the first change, status\npages would be freed.  During the second change they would be allocated\nagain.  Hence across the full pair of change the addresses of the status\npages may change, rendering stale previously calculated pointers into the\nstatus array."
        }
      ],
      "impacts": [
        {
          "descriptions": [
            {
              "lang": "en",
              "value": "An unprivileged guest may be able to elevate its privileges to that of the\nhost.  Information leaks and Denial of Service (DoS) are possible as well."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-13T15:44:42.370Z",
        "orgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
        "shortName": "XEN"
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      "references": [
        {
          "url": "https://xenbits.xenproject.org/xsa/advisory-517.html"
        }
      ],
      "title": "grant-table: double version change race",
      "workarounds": [
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          "lang": "en",
          "value": "Using the \"gnttab=max-ver:1\" hypervisor command line option will avoid\nthe vulnerability.\n\nUsing the \"max_grant_version=1\" guest configuration option for guests will\nalso avoid the vulnerability."
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "23aa2041-22e1-471f-9209-9b7396fa234f",
    "assignerShortName": "XEN",
    "cveId": "CVE-2026-79610",
    "datePublished": "2026-10-13T15:44:42.370Z",
    "dateReserved": "2026-08-25T07:35:05.290Z",
    "dateUpdated": "2026-10-13T16:13:47.749Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-79610",
      "date": "2026-10-14",
      "epss": "0.0018",
      "percentile": "0.0708"
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    "nvd": {
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            "affectedData": [
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                "defaultStatus": "unknown",
                "product": "Xen",
                "vendor": "Xen",
                "versions": [
                  {
                    "status": "unknown",
                    "version": "consult Xen advisory XSA-517"
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        "descriptions": [
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            "value": "XSA-501 was about issues with v1 -\u003e v2 and v2 -\u003e v1 changes racing certain\nother grant table operations.  Sadly a v2 -\u003e v1 -\u003e v2 change has yet\nanother effect which wasn\u0027t accounted for: During the first change, status\npages would be freed.  During the second change they would be allocated\nagain.  Hence across the full pair of change the addresses of the status\npages may change, rendering stale previously calculated pointers into the\nstatus array."
          }
        ],
        "id": "CVE-2026-79610",
        "lastModified": "2026-10-14T16:10:14.750",
        "metrics": {},
        "published": "2026-10-13T16:17:23.247",
        "references": [
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        "sourceIdentifier": "security@xen.org",
        "vulnStatus": "Awaiting Analysis"
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