CVE-2026-34085: Fontconfig Project Fontconfig

High severity, CVSS 7.8. EPSS: 0.2% chance of exploitation in the next 30 days.

fontconfig before 2.17.1 has an off-by-one error in allocation during sfnt capability handling, leading to a one-byte out-of-bounds write, and potentially a crash or code execution. This is in FcFontCapabilities in fcfreetype.c.

Affected products

• Fontconfig Project Fontconfig: version 2.17.0 only

Published 2026-03-25. Last modified 2026-06-17.