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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-50256 Detail

Description

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. A mismatch between the X server and the libXfont2 library's maximum font name length can cause a stack buffer overflow during font alias resolution. The server allocates a 256 byte stack buffer but libXfont2's alias target name length is 1024 bytes. A font alias name between 257 and 1023 bytes causes the X server to copy that name into the undersized stack buffer without further checks. 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.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://access.redhat.com/security/cve/CVE-2026-50256 Red Hat, Inc.
https://bugzilla.redhat.com/show_bug.cgi?id=2485380 Red Hat, Inc.
https://gitlab.freedesktop.org/xorg/xserver/-/commit/bb5158f962dc935e58ef8b4b5fcb31be201a6e07 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-2026-50256
NVD Published Date:
06/05/2026
NVD Last Modified:
06/05/2026
Source:
Red Hat, Inc.