CVE-2026-55999

HIGH

xorg-server / xwayland glamor font atlas Heap Buffer Overflow

Title source: cna

Description

Local attackers with a X connection able to provide PCX fonts to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a heap buffer overflow via SetFont due to missing glyph boundary checks.

References (2)

Core 2

Core References

Patch patch

https://gitlab.freedesktop.org/xorg/xserver/-/commit/fbf7bac22e2c6bd627fb042742a23318263edae1

Vendor Advisory vendor-advisory

https://www.openwall.com/lists/oss-security/2026/07/08/2

Scores

CVSS v3 8.5

EPSS 0.0027

EPSS Percentile 18.9%

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

CISA SSVC

Vulnrichment

Exploitation none

Automatable no

Technical Impact total

Details

CWE

CWE-122

Status published

Products (4)

x.org/x_server < 21.2.24

X.Org/xorg-server < 21.1.24

X.Org/xwayland < 24.1.13

x.org/xwayland < 24.1.13

Published Jul 08, 2026

Tracked Since Jul 08, 2026