CVE-2026-23554 Use after free of paging structures in EPT

High 7.8 Published 23 Mar 2026 Updated 23 Mar 2026

A use-after-free in Xen's EPT paging allows attackers to access unintended memory regions, potentially leading to data exposure or privilege escalation.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2026-23554?

CVE-2026-23554 is a high-severity use after free vulnerability in Xen Xen, published on 23 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

The Intel EPT paging code uses an optimization to defer flushing of any cached EPT state until the p2m lock is dropped, so that multiple modifications done under the same locked region only issue a single flush.

Freeing of paging structures however is not deferred until the flushing is done, and can result in freed pages transiently being present in cached state. Such stale entries can point to memory ranges not owned by the guest, thus allowing access to unintended memory regions.

Weakness: CWE-367

Which versions are affected by CVE-2026-23554?

It affects 1 product.

Linux distribution packages (5)

`xen` SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOS	All versions	`4.17.6_06-150500.3.62.2`
`xen` SUSE:Linux Enterprise High Performance Computing 15 SP5-LTSS	All versions	`4.17.6_06-150500.3.62.2`
`xen` SUSE:Linux Enterprise Micro 5.5	All versions	`4.17.6_06-150500.3.62.2`
`xen` SUSE:Linux Enterprise Server 15 SP5-LTSS	All versions	`4.17.6_06-150500.3.62.2`
`xen` SUSE:Linux Enterprise Server for SAP Applications 15 SP5	All versions	`4.17.6_06-150500.3.62.2`

Products include Xen Xen.

How do I fix CVE-2026-23554?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2026-23554 being exploited?

There is no known exploitation of CVE-2026-23554 in the wild and no public exploit code.

All Xen Xen vulnerabilities

Sources

Also known as ALPINE-CVE-2026-23554, DEBIAN-CVE-2026-23554, GHSA-h6vw-38xq-3xwx, MGASA-2026-0068, SUSE-SU-2026:1092-1, UBUNTU-CVE-2026-23554.