CVE-2026-23558

What it is

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.

At a glance

Exploitability

Can be exploited locally on the machine with a low-privilege account. High risk of data exposure, data tampering, service disruption.

Exploit odds

0.1% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-05-19 14:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-14 20:10 UTC Last updatedMost recent change to the record

Details

Published

2026-05-19 14:16 UTC

Last modified

2026-10-14 20:10 UTC

Exploit probability

0.1% · EPSS, next 30 days

Weakness

CWE-362 · Race condition

Record status

Analyzed

Affected

• Xen

Attack profile CVSS 3.1 · 7.8

Attack vector

Local

Complexity

High

Privileges needed

Low

User interaction

None

Scope

Changed

Confidentiality

High

Integrity

High

Availability

High