Xorg: xwayland: use-after-free in syncinittrigger()

Summary

A use-after-free flaw was found in X.Org and Xwayland. When changing an alarm, the values of the change mask are evaluated one after the other, changing the trigger values as requested, and eventually, SyncInitTrigger() is called. If one of the changes triggers an error, the function will return early, not adding the new sync object, possibly causing a use-after-free when the alarm eventually triggers.

Timeline

1. Feb 25, 2025, 3:55 PM UTCCVE published
2. Feb 25, 2025, 4:08 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: total

3. Jun 29, 2026, 8:37 PM UTCRecord last updated

Affected versions

• xserver

  fixed in 21.1.16; From 22.0.0 · fixed in 24.1.6

• xorg-x11-server-Xwayland

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• xorg-x11-server

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• xorg-x11-server

  Version range not reported

• xorg-x11-server-Xwayland

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• tigervnc

  Version range not reported

• xorg-x11-server

  Version range not reported

• xorg-x11-server

  Version range not reported

• xorg-x11-server-Xwayland

  Version range not reported

References 17