CVE-2017-13720: X.org Libxfont

High severity, CVSS 7.1. EPSS: 0.4% chance of exploitation in the next 30 days.

In the PatternMatch function in fontfile/fontdir.c in libXfont through 1.5.2 and 2.x before 2.0.2, an attacker with access to an X connection can cause a buffer over-read during pattern matching of fonts, leading to information disclosure or a crash (denial of service). This occurs because '\0' characters are incorrectly skipped in situations involving ? characters.

Affected products

• X.org Libxfont: up to and including 1.5.2; version 2.0.0 only; version 2.0.1 only

Published 2017-10-11. Last modified 2026-06-17.