fontus PyPI malware: fingerprinting/exfiltration package (no CVE)
Severity: medium · Patch status: no-fix-needed · Since 2026-10-25
OpenSSF and GitHub advisory GHSA-g5mh-f2v3-6p25 (published 2026-10-25) flag the PyPI package 'fontus' as malicious. Versions 0.0.1–0.0.3 contain code that performs system fingerprinting, exfiltrating basic information such as IP address, username, and the list of available fonts, with no other functionality. The campaign is categorized PROBABLYPENTEST with limited risk, and CWE-506 (embedded malicious code) is noted. No patched versions exist; the package is malware and should not be used. Anyone who installed fontus should treat the exfiltrated data as leaked and remove the package.
What to do
- Remove/uninstall fontus from all environments and block it in dependency policies
- Audit install logs and CI for any use of fontus
- Rotate credentials or tokens if installs ran on sensitive hosts
- Assess what host data (IP, username, fonts) may have been exfiltrated and whether it creates risk
- Add the package and its hashes to internal blocklists/SCA denylists
Sources
All live incidents on Threat Watch
