Vulnerability · Published Jul 8, 2026 · Assigned by suse

CVE-2026-56000xorg-x11-server / xwayland GLX contextTags Use-After-Free in CommonMakeCurrent()

Critical 9.0

In plain English

A critical-severity use-after-free in xorg-x11-server from X.Org. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)9.0Critical
Exploit odds (30 days)0.3%top 76.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Local attackers with a X connection able to provide GLX commit to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a Heap Use After Free, due to CommonMakeCurrent() pointing into potentially reallocated memory.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
AlmaLinux:10xorg-x11-server-Xwayland24.1.9-4.el10_2.3ALSA-2026:38489
AlmaLinux:9xorg-x11-server-Xwayland24.1.9-4.el9_8.3ALSA-2026:38490
AlmaLinux:10xorg-x11-server-Xwayland-devel24.1.9-4.el10_2.3ALSA-2026:38489
AlmaLinux:9xorg-x11-server-Xwayland-devel24.1.9-4.el9_8.3ALSA-2026:38490
Alpine:v3.24xorg-server21.1.24-r0ALPINE-CVE-2026-56000
Alpine:v3.24xwayland24.1.13-r0ALPINE-CVE-2026-56000
Debian:12xorg-serverno fix listedDEBIAN-CVE-2026-56000
Debian:13xorg-server2:21.1.16-1.3+deb13u4DEBIAN-CVE-2026-56000
Debian:14xorg-server2:21.1.24-1DEBIAN-CVE-2026-56000
Debian:12xwaylandno fix listedDEBIAN-CVE-2026-56000
Debian:13xwaylandno fix listedDEBIAN-CVE-2026-56000
Debian:14xwayland2:24.1.13-1DEBIAN-CVE-2026-56000
Rocky Linux:10xorg-x11-server-Xwayland0:24.1.9-4.el10_2.3RLSA-2026:38489
Rocky Linux:9xorg-x11-server-Xwayland0:24.1.9-4.el9_8.3RLSA-2026:38490
Ubuntu:22.04:LTSxorg-serverno fix listedUBUNTU-CVE-2026-56000
Ubuntu:24.04:LTSxorg-serverno fix listedUBUNTU-CVE-2026-56000
Ubuntu:25.10xorg-serverno fix listedUBUNTU-CVE-2026-56000
Ubuntu:26.04:LTSxorg-serverno fix listedUBUNTU-CVE-2026-56000
Ubuntu:26.10xorg-serverno fix listedUBUNTU-CVE-2026-56000
Ubuntu:22.04:LTSxwaylandno fix listedUBUNTU-CVE-2026-56000
Ubuntu:24.04:LTSxwaylandno fix listedUBUNTU-CVE-2026-56000
Ubuntu:25.10xwaylandno fix listedUBUNTU-CVE-2026-56000
Ubuntu:26.04:LTSxwaylandno fix listedUBUNTU-CVE-2026-56000
Ubuntu:26.10xwaylandno fix listedUBUNTU-CVE-2026-56000

Affected products (as reported)

VendorProductVersions
X.Org xorg-x11-server 0 – before 21.1.24
X.Org xwayland 0 – before 24.1.13

Weakness: CWE-416 · Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

References