CVE-2025-66034

CRITICAL EPSS 38.8%
Published Nov 29, 20257mo ago · Modified Jun 17, 20262w ago
9.8 CVSS 3.1
Critical
Find Similar
Published Nov 29, 2025 7mo ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
9.8
Exploitability
3.9
Impact
5.9
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
38.8% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-91

Affected Products 1

VendorProductVersionRange
fonttoolsfonttools*≥4.33.0  –  <4.60.2

References 2

  • github.com https://github.com/fonttools/fonttools/commit/a696d5ba93270d5954f98e7cab5ddca8a02c1e32
    Patch
  • github.com https://github.com/fonttools/fonttools/security/advisories/GHSA-768j-98cg-p3fv
    ExploitVendor Advisory

Remediation

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