CVE-2026-56002: x libxfont Heap-based Buffer Overflow

Vulnerability summary

CVE-2026-56002 is a high (CVSS 8.8) Heap-based Buffer Overflow vulnerability in x libxfont. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 35.6% of scored vulnerabilities.

Timeline

1. 08-07-2026
   PublishedVulnerability first disclosed.
2. 09-07-2026
   Last modifiedVulnerability information updated.

Description

A heap bufferflow in pcfReadFont() due to missing glyph bounds checking in libXfont2 before 2.0.8  allows attackers authenticated as X client to execute code within the X server.

• CWE-122Heap-based Buffer OverflowA heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().