Detections
Analytics
CVE-2026-50257
high
Description
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
https://lists.x.org/archives/xorg-announce/2026-June/003702.html
https://bugzilla.redhat.com/show_bug.cgi?id=2485382
https://access.redhat.com/security/cve/CVE-2026-50257
https://access.redhat.com/errata/RHSA-2026:29844
https://access.redhat.com/errata/RHSA-2026:28923
https://access.redhat.com/errata/RHSA-2026:26709
https://access.redhat.com/errata/RHSA-2026:26610
https://access.redhat.com/errata/RHSA-2026:26590