PT-2025-48353 · Fonttools · Fonttools

Published 2025-11-29 · Updated 2025-11-29 · CVE-2025-66034

Positive Technologies · (AI Summary)

CVSS v3.1

6.3

6.3

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions fontTools versions 4.33.0 through 4.60.1

Description fontTools is a Python library used for manipulating fonts. Versions from 4.33.0 up to, but not including, 4.60.2 contain a file write issue within the

varLib

script (or when using

python3 -m fontTools.varLib

). This can lead to remote code execution when processing a malicious

.designspace

file. The issue resides in the

main()

code path of

fontTools.varLib

, which is utilized by the

fontTools varLib

command-line interface and any code that calls

fontTools.varLib.main()

.

Recommendations Update to fontTools version 4.60.2 or later.

Fix

RCE

Weakness Enumeration

CWE-91

Related Identifiers

CVE-2025-66034

Affected Products

Fonttools

References · 5

• https://nvd.nist.gov/vuln/detail/CVE-2025-66034 · Security Note
• https://github.com/fonttools/fonttools/commit/a696d5ba93270d5954f98e7cab5ddca8a02c1e32 · Note
• https://github.com/fonttools/fonttools/security/advisories/GHSA-768j-98cg-p3fv · Note
• https://twitter.com/CVEnew/status/1994599560623149359 · Twitter Post
• https://twitter.com/VulmonFeeds/status/1994579914863821274 · Twitter Post