Use After Free Affecting tigervnc-server-module package, versions <0:1.15.0-7.el9_8.2


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-ALMALINUX9-TIGERVNCSERVERMODULE-17705532
  • published30 Jun 2026
  • disclosed17 Jun 2026

Introduced: 17 Jun 2026

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

How to fix?

Upgrade AlmaLinux:9 tigervnc-server-module to version 0:1.15.0-7.el9_8.2 or higher.
This issue was patched in ALSA-2026:29844.

NVD Description

Note: Versions mentioned in the description apply only to the upstream tigervnc-server-module package and not the tigervnc-server-module package as distributed by AlmaLinux. See How to fix? for AlmaLinux:9 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