CVE-2025-66034

Published: Nov 29, 2025Modified: Jun 17, 2026

9.8

Vector

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

Exploitability: 3.9 / Impact: 5.9

Source: NVD

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.

Affected (1)

Products: Fonttools: Fonttools

1 product

Configuration A

1 vulnerable

Vulnerable Software	Affected Versions
Fonttools Fonttools	From 4.33.0 to 4.60.2

Related CWEs

XML Injection (aka Blind XPath Injection)

The product does not properly neutralize special elements that are used in XML, allowing attackers to modify the syntax, content, or commands of the XML before it is processed by an end system.

References (3)

https://github.com/fonttools/fonttools/commit/a696d5ba93270d5954f98e7cab5ddca8a02c1e32

Source: security-advisories@github.com

Patch

https://github.com/fonttools/fonttools/security/advisories/GHSA-768j-98cg-p3fv

Source: security-advisories@github.com

ExploitVendor Advisory

https://github.com/fonttools/fonttools/security/advisories/GHSA-768j-98cg-p3fv

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

ExploitVendor Advisory

Timeline

No history available yet.