CVE-2025-66034
criticalfontTools is a library for manipulating fonts, written in Python.
Vendor / product: Fonttools — fonttools
fontTools is a library for manipulating fonts, written in Python. In versions from 4.33.0 to before 4.60.2, the fonttools varLib (or python3 -m fontTools.varLib) script has an arbitrary file write vulnerability that leads to remote code execution when a malicious .designspace file is processed. The vulnerability affects the main() code path of fontTools.varLib, used by the fonttools varLib CLI and any code that invokes fontTools.varLib.main(). This issue has been patched in version 4.60.2.
CVSS
9.8
9.8 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2025-11-29 01:16
Modified: 2026-10-18 18:10
NVD status: Analyzed
Last synced 2 days ago
Verified against the source API 2026-10-27 07:06 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
fonttools / fonttools ≥4.33.0 <4.60.2
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
References
- https://github.com/fonttools/fonttools/commit/a696d5ba93270d5954f98e7cab5ddca8a02c1e32 security-advisories@github.com
- https://github.com/fonttools/fonttools/security/advisories/GHSA-768j-98cg-p3fv security-advisories@github.com
- https://github.com/fonttools/fonttools/security/advisories/GHSA-768j-98cg-p3fv 134c704f-9b21-4f2e-91b3-4a467353bcc0
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 07:06 UTC · record ↗