CVE-2025-66034 - CVE House
Back to Database
Status published Medium CVE-2025-66034

fontTools is Vulnerable to Arbitrary File Write and XML injection in fontTools.varLib

Vulnerability 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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

THREAT MONITOR

Am I Vulnerable?

Launch our assessment wizard to check if your infrastructure is exposed to • CVE-2025-66034

Credits & Attribution

No credits recorded in the NVD database.

References

More from fonttools

View All →
CVE-2023-45139
fonttools XML External Entity Injection (XXE) Vulnerability
High 7.5

Affected Vendor

Affected Software

fonttools
Vulnerable Versions:
>= 4.33.0, < 4.60.2

Timeline

Official Publish: November 29th, 2025
Last Modified: December 1st, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:L

Weaknesses (CWE)

CWE-91

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.