CVE-2026-79610

grant-table: double version change race

Published Oct 13, 2026 CVSS 3.1 · 8.8 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

Vendor Workaround

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

Tracking

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Advisories

Source ID Title
Debian DLA Debian DLA DLA-4818-1 xen security update
Debian DLA Debian DLA DLA-4881-1 xen security update
Debian DSA Debian DSA DSA-6571-1 xen security update
History
Type Values Removed Values Added
Weaknesses CWE-416
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 8.8, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Xen
Xen xen
Vendors & Products Xen
Xen xen
Type Values Removed Values Added
Weaknesses CWE-362
CWE-416
Type Values Removed Values Added
Description 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.
Title grant-table: double version change race
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
XEN
Published
Updated
Oct 20, 2026, 5:33 PM
Reserved
Aug 25, 2026, 7:35 AM
Status
Awaiting Analysis
Published
Oct 13, 2026, 4:17 PM
Modified
Oct 20, 2026, 6:17 PM