CVE-2026-23558

grant table v2 race in status page mapping

Published May 19, 2026 CVSS 3.1 · 7.8 High EPSS < 1% KEV · Not listed
Description
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.

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 HVM and PVH 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 DSA Debian DSA DSA-6424-1 xen security update
History
Type Values Removed Values Added
CPEs cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*
Type Values Removed Values Added
Weaknesses CWE-362
Metrics cvssV3_1

{'score': 7.8, 'vector': 'CVSS:3.1/AV:L/AC:H/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
Description 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.
Title grant table v2 race in status page mapping
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
XEN
Published
Updated
May 20, 2026, 3:55 AM
Reserved
Jan 14, 2026, 1:07 PM
Status
Analyzed
Published
May 19, 2026, 2:16 PM
Modified
Oct 14, 2026, 8:10 PM