CVE-2025-66034

low-risk
Published 2025-11-29

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.

Do I need to act?

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0.12% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
6
CVSS 6.3/10 Medium
LOCAL / HIGH complexity

Affected Products (1)

Fonttools

Affected Vendors

22
/ 100
low-risk
Severity 16/34 · Moderate
Exploitability 1/34 · Minimal
Exposure 5/34 · Minimal