CVE-2026-50256

HIGH EPSS 4.7%
Published Jun 5, 20263w ago · Modified Jun 24, 20265d ago
7.8 CVSS 3.1
High
Find Similar
Published Jun 5, 2026 3w ago
Last Modified Jun 24, 2026 5d ago

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.

CVSS Details

Base Score
7.8
Exploitability
1.8
Impact
5.9
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
4.7% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-121

Affected Products 6

VendorProductVersionRange
x.orgx_server* <21.1.23
x.orgxwayland* <24.1.12
redhatenterprise_linux7.0any
redhatenterprise_linux8.0any
redhatenterprise_linux9.0any
redhatenterprise_linux10.0any

References 11

Remediation

  • gitlab.freedesktop.org https://gitlab.freedesktop.org/xorg/xserver/-/commit/bb5158f962dc935e58ef8b4b5fcb31be201a6e07
    Patch