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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-50258 Detail

Description

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

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URL Source(s) Tag(s)
https://access.redhat.com/security/cve/CVE-2026-50258 Red Hat, Inc.
https://bugzilla.redhat.com/show_bug.cgi?id=2485383 Red Hat, Inc.
https://gitlab.freedesktop.org/xorg/xserver/-/commit/543e108516428fc8c3bea91d6563ad266f9a801e Red Hat, Inc.
https://lists.x.org/archives/xorg-announce/2026-June/003702.html Red Hat, Inc.
https://redhat.atlassian.net/browse/PSIRTSUPT-16950 Red Hat, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-121 Stack-based Buffer Overflow Red Hat, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-50258
NVD Published Date:
06/05/2026
NVD Last Modified:
06/05/2026
Source:
Red Hat, Inc.