CVE-2026-23558

grant table v2 race in status page mapping

HIGH
7.8
CVSS Score
Published: May 19, 2026 at 12:49 PM UTC
Updated: October 14, 2026 at 08:10 PM UTC
1 product affected across 1 vendorXen

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Severity
HIGH7.8
Exploit prediction
EPSS 0.1%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Xen· Xenwordpress-plugin
95%
v ≥ 4.0.0
Vendor states this is fixed in consult Xen advisory XSA-486 (unknown)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (3)

MitigationPatchVendor Advisory
Source: cverecord
https://xenbits.xenproject.org/xsa/advisory-486.html
Mailing ListMitigationPatchThird Party Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://www.openwall.com/lists/oss-security/2026/04/28/13
MitigationPatchVendor Advisory
Source: af854a3a-2127-422b-91ae-364da2661108
http://xenbits.xen.org/xsa/advisory-486.html

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.8HIGHCISA-ADP
Attack Vector
LOCAL
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-362

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