PT-2026-46937 · Red Hat · Red Hat Enterprise Linux 10+4

Published 2026-06-05 · Updated 2026-06-05 · CVE-2026-50257

Mitre

CVSS v3.1

7.8

High

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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.

Fix

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

CVE-2026-50257

Affected Products

Red Hat Enterprise Linux 10

Red Hat Enterprise Linux 6

Red Hat Enterprise Linux 7

Red Hat Enterprise Linux 8

Red Hat Enterprise Linux 9

References · 6

• https://nvd.nist.gov/vuln/detail/CVE-2026-50257 · Security Note
• https://gitlab.freedesktop.org/xorg/xserver/-/commit/f5abfb61994471023d8c6470428c8e30c411cc0b · Note
• https://bugzilla.redhat.com/show_bug.cgi?id=2485382 · Note
• https://access.redhat.com/security/cve/CVE-2026-50257 · Note
• https://redhat.atlassian.net/browse/PSIRTSUPT-16950 · Note
• https://lists.x.org/archives/xorg-announce/2026-June/003702.html · Note