Use After Free Affecting xorg-x11-server-Xwayland package, versions <0:21.1.3-20.el8_10.2


Severity

Recommended
0.0
high
0
10

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.15% (6th percentile)

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  • Snyk IDSNYK-ALMALINUX8-XORGX11SERVERXWAYLAND-17372425
  • published18 Jun 2026
  • disclosed17 Jun 2026

Introduced: 17 Jun 2026

CVE-2026-50261  (opens in a new tab)
CWE-416  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:8 xorg-x11-server-Xwayland to version 0:21.1.3-20.el8_10.2 or higher.
This issue was patched in ALSA-2026:26562.

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:8 relevant fixed versions and status.

A use-after-free flaw was found in the X.Org X server and Xwayland in SyncChangeCounter(). A client that sets up multiple SyncCounters can trigger a use-after-free when destroying those counters via a second client connection while changing those counters. 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