CVE-2026-50261 – Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in syncchangecounter()

CVE ID :CVE-2026-50261

Published : June 5, 2026, 12:16 p.m. | 16 minutes ago

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.

Severity: 7.8 | HIGH

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