CVE-2026-50260 PUBLISHED

Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: use-after-free in freecounter()

Assigner: redhat
Reserved: 04.06.2026 Published: 05.06.2026 Updated: 05.06.2026

A use-after-free flaw was found in the X.Org X server and Xwayland in FreeCounter(). A client that sets up multiple SyncCounters and awaits on those triggers can trigger a use-after-free when destroying those counters via a second client connection. This may be used to crash the server, or for privilege escalation if the X server runs as root.

Metrics

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS Score: 7.8

Product Status

Vendor Red Hat
Product Red Hat Enterprise Linux 10
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 6
Versions Default: unknown
Vendor Red Hat
Product Red Hat Enterprise Linux 7
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 8
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 8
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 9
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 9
Versions Default: affected

Credits

  • Upstream acknowledges Anonymous (Trend Micro Zero Day Initiative) as the original reporter.

References

Problem Types

  • Use After Free CWE