Executive brief
GNOME Fonts Viewer is a utility used to preview and install font files on Linux systems. A security vulnerability in version 3.34.0 allows a malicious font file to crash the application or exhaust system memory. This could lead to a denial-of-service, preventing users from viewing fonts or potentially causing system instability if memory resources are fully depleted.
Technical details
A heap corruption vulnerability exists in GNOME Fonts Viewer 3.34.0 due to improper handling of TrueType Font (TTF) files. An attacker can craft a malicious TTF file containing an oversized pattern that triggers an out-of-bounds write and an infinite or excessive malloc() loop. This root cause leads to heap exhaustion and a subsequent crash of the gnome-font-viewer process. While the attack vector is categorized as local/physical via file opening, it can be triggered whenever a user attempts to preview a malicious font file. A public exploit (EDB-48803) is available, demonstrating the memory exhaustion via a Python-generated TTF header.
Affected products
- GNOME Fonts Viewer 3.34.0
Timeline
- 2020-09-10: other: Exploit code authored by Cody Winkler
- 2020-09-11: disclosed: Exploit published on Exploit-DB
- 2026-01-29: advisory: NVD and VulnCheck advisory published