Stack-based Buffer Overflow Affecting xorg-x11-server-common package, versions <0:1.20.11-8.el8_6


Severity

Recommended
0.0
high
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.16% (6th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-RHEL8-XORGX11SERVERCOMMON-17911258
  • published9 Jul 2026
  • disclosed2 Jun 2026

Introduced: 2 Jun 2026

CVE-2026-50258  (opens in a new tab)
CWE-121  (opens in a new tab)

How to fix?

Upgrade RHEL:8 xorg-x11-server-common to version 0:1.20.11-8.el8_6 or higher.
This issue was patched in RHSA-2026:36791.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xorg-x11-server-common package and not the xorg-x11-server-common package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has multiple stack buffers sized XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify or clamp non-canonical key types to XkbMaxShiftLevel. A client can change key types to excessive shift levels and trigger stack overflows. This is caused by an incomplete fix of CVE-2025-26597. This may be used to crash the server, or for privilege escalation if the X server runs as root.

CVSS Base Scores

version 3.1