Use After Free Affecting xorg-x11-server-Xwayland package, versions <0:24.1.9-4.el10_2.2


Severity

Recommended
0.0
high
0
10

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.14% (4th percentile)

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  • Snyk IDSNYK-ALMALINUX10-XORGX11SERVERXWAYLAND-18764585
  • published14 Aug 2026
  • disclosed25 Jun 2026

Introduced: 25 Jun 2026

CVE-2026-50257  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:10 xorg-x11-server-Xwayland to version 0:24.1.9-4.el10_2.2 or higher.
This issue was patched in ALSA-2026:26566.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xorg-x11-server-Xwayland package and not the xorg-x11-server-Xwayland package as distributed by AlmaLinux. See How to fix? for AlmaLinux:10 relevant fixed versions and status.

A use-after-free flaw was found in the X.Org X server and Xwayland in miSyncDestroyFence(). A client that sets up multiple fence triggers can trigger a use-after-free function pointer call. An attacker would connect to the X server to set up a fence and await that fence, then a second X connection destroys the fence, causing the use-after-free. This may be used to crash the server, or for privilege escalation if the X server runs as root.

References

CVSS Base Scores

version 3.1