CVE-2026-55999

Name of the Vulnerable Software and Affected Versions xorg-server versions prior to 21.2.24 xwayland versions prior to 24.1.13

Description Local attackers with an X connection can cause a heap buffer overflow by providing PCX fonts to the X server. This occurs due to missing glyph boundary checks within the SetFont() function. A heap buffer overflow is a memory corruption issue where a program writes more data to a heap-allocated buffer than it can hold, potentially leading to crashes or arbitrary code execution.

Recommendations Update xorg-server to version 21.2.24 or later. Update xwayland to version 24.1.13 or later.