grant table v2 race in status page mapping

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Summary

CVECVE-2026-23558
StatePUBLISHED
AssignerXEN
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-05-19 14:16:38 UTC
Updated2026-05-19 18:55:19 UTC
DescriptionThe 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.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from ADP

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

EPSS: 0.000120000 probability, percentile 0.017590000 (date 2026-05-26)

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

VersionSourceTypeScoreSeverityVector
3.1ADPDECLARED7.8HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
3.1134c704f-9b21-4f2e-91b3-4a467353bcc0Secondary7.8HIGHCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Xen Xen All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Xen Xen unknown consult Xen advisory XSA-486 Not specified

References

ReferenceSourceLinkTags
www.openwall.com/lists/oss-security/2026/04/28/13 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com Mailing List, Mitigation, Patch, Third Party Advisory
xenbits.xenproject.org/xsa/advisory-486.html [email protected] xenbits.xenproject.org Mitigation, Patch, Vendor Advisory
xenbits.xen.org/xsa/advisory-486.html af854a3a-2127-422b-91ae-364da2661108 xenbits.xen.org Mitigation, Patch, Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: This issue was discovered by Claude Opus 4.6 and diagnosed as a security issue by Rafal Wojtczuk. (en)

Additional Advisory Data

Workarounds

CNA: Using the "gnttab=max-ver:1" hypervisor command line option will avoid the vulnerability. Using the "max_grant_version=1" guest configuration option for HVM and PVH guests will also avoid the vulnerability.

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