Use After Free in X.org Xorg-X11-Server
CVE-2026-56000
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.
Vulnerability class: Use-After-Free
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.003 (21.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 22nd percentile — 21.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.003 · change: +0.001
Affected products
- X.org Xorg-X11-Server — versions 0
- X.org X Server
- X.org Xwayland — versions 0
Weakness classification (CWE)
References
- gitlab.freedesktop.org/xorg/xserver/-/commit/2779affbdb4354e894f490e56f962527d6… (Patch, patch)
- www.openwall.com/lists/oss-security/2026/07/08/2 (vendor-advisory, Patch, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2026-56000?
- CVE-2026-56000 is a high-severity vulnerability in X.org Xorg-X11-Server, classified under Use After Free. CVSS score: 7.8/10. Published 2026-07-08.
- How severe is CVE-2026-56000?
- High severity. CVSS v3 base score is 7.8 out of 10.