CVE-2025-66034
fontTools is Vulnerable to Arbitrary File Write and XML injection in fontTools.varLib
6.3
MEDIUM
CVSS 3.1
EPSS 0.08%
Description
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.
How to fix CVE-2025-66034
To remediate CVE-2025-66034, upgrade the affected package to a fixed version below.
- —no fix listed
- —upgrade to 4.60.2 or later
Is CVE-2025-66034 being exploited?
Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0
- >= 4.33.0, < 4.60.2
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM6.3 | CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:L |