CVE-2025-66034 – fontTools is Vulnerable to Arbitrary File Write and XML injection in fontTools.varLib

The following table lists the changes that have been made to the
CVE-2025-66034 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution
of a vulnerability, and for identifying the most recent changes that may
impact the vulnerability’s severity, exploitability, or other characteristics.

  • New CVE Received
    by [email protected]

    Nov. 29, 2025

    Action Type Old Value New Value
    Added 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.
    Added CVSS V3.1 AV:L/AC:H/PR:N/UI:R/S:C/C:N/I:H/A:L
    Added CWE CWE-91
    Added Reference https://github.com/fonttools/fonttools/commit/a696d5ba93270d5954f98e7cab5ddca8a02c1e32
    Added Reference https://github.com/fonttools/fonttools/security/advisories/GHSA-768j-98cg-p3fv
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