Stack-based Buffer Overflow The advisory has been revoked - it doesn't affect any version of package xorg-x11-server (opens in a new tab)

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Snyk IDSNYK-RHEL8-XORGX11SERVER-17223672
published7 Jun 2026
disclosed2 Jun 2026

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Introduced: 2 Jun 2026

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

Amendment

The Red Hat security team deemed this advisory irrelevant for RHEL:8.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xorg-x11-server package and not the xorg-x11-server package as distributed by RHEL.

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.