Detections
Analytics
CVE-2026-50261
high
Description
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
https://redhat.atlassian.net/browse/PSIRTSUPT-16950
https://lists.x.org/archives/xorg-announce/2026-June/003702.html
https://gitlab.freedesktop.org/xorg/xserver/-/commit/bdd7bf57af208b1ddf57d4683d67104443b44812