CVE-2025-66034
November 29, 2025
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.
Affected Packages
fonttools (CONDA):
Affected version(s) >=4.33.0 <4.60.2Fix Suggestion:
Update to version 4.60.2https://github.com/fonttools/fonttools.git (GITHUB):
Affected version(s) >=4.33.0 <4.60.2Fix Suggestion:
Update to version 4.60.2fonttools (PYTHON):
Affected version(s) >=4.33.0 <4.60.2Fix Suggestion:
Update to version 4.60.2Related Resources (4)
Do you need more information?
Contact UsCVSS v4
Base Score:
6.9
Attack Vector
LOCAL
Attack Complexity
HIGH
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
PASSIVE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
HIGH
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
HIGH
Subsequent System Availability
LOW
CVSS v3
Base Score:
6.3
Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
LOW
Weakness Type (CWE)
XML Injection (aka Blind XPath Injection)
EPSS
Base Score:
0.23
