CVE-2026-23558 (GCVE-0-2026-23558)

Vulnerability from cvelistv5 – Published: 2026-05-19 12:49 – Updated: 2026-05-20 03:55
VLAI?
Title
grant table v2 race in status page mapping
Summary
The adjustments made for XSA-379 as well as those subsequently becoming XSA-387 still left a race window, when a HVM or PVH guest does a grant table version change from v2 to v1 in parallel with mapping the status page(s) via XENMEM_add_to_physmap. Some of the status pages may then be freed while mappings of them would still be inserted into the guest's secondary (P2M) page tables.
Severity ?
7.8 (High)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CWE
  • CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Assigner
XEN
References
Impacted products
Vendor Product Version
Xen Xen Unknown: consult Xen advisory XSA-486
Create a notification for this product.
Credits
This issue was discovered by Claude Opus 4.6 and diagnosed as a security issue by Rafal Wojtczuk.
Show details on NVD website
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            "url": "http://www.openwall.com/lists/oss-security/2026/04/28/13"
          },
          {
            "url": "http://xenbits.xen.org/xsa/advisory-486.html"
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              "attackVector": "LOCAL",
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              "baseScore": 7.8,
              "baseSeverity": "HIGH",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "LOW",
              "scope": "CHANGED",
              "userInteraction": "NONE",
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                "id": "CVE-2026-23558",
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                    "Technical Impact": "total"
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                "role": "CISA Coordinator",
                "timestamp": "2026-05-19T00:00:00+00:00",
                "version": "2.0.3"
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                "description": "CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization (\u0027Race Condition\u0027)",
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                "type": "CWE"
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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        "title": "CISA ADP Vulnrichment"
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          "value": "All Xen versions from 4.0 onwards are affected.  Xen versions 3.4 and\nolder are not affected.\n\nOnly x86 HVM and PVH guests permitted to use grant table version 2\ninterfaces can leverage this vulnerability.  x86 PV guests cannot\nleverage this vulnerability.  On Arm, grant table v2 use is explicitly\nunsupported."
        }
      ],
      "credits": [
        {
          "lang": "en",
          "type": "finder",
          "value": "This issue was discovered by Claude Opus 4.6 and diagnosed as a security\nissue by Rafal Wojtczuk."
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      "descriptions": [
        {
          "lang": "en",
          "value": "The adjustments made for XSA-379 as well as those subsequently becoming\nXSA-387 still left a race window, when a HVM or PVH guest does a grant\ntable version change from v2 to v1 in parallel with mapping the status\npage(s) via XENMEM_add_to_physmap.  Some of the status pages may then be\nfreed while mappings of them would still be inserted into the guest\u0027s\nsecondary (P2M) page tables."
        }
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      "title": "grant table v2 race in status page mapping",
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          "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 HVM and PVH\nguests will also avoid the vulnerability."
        }
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    "datePublished": "2026-05-19T12:49:54.652Z",
    "dateReserved": "2026-01-14T13:07:36.961Z",
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    "state": "PUBLISHED"
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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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