XML Injection Affecting fonttools package, versions [4.33.0,4.61.0)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-FONTTOOLS-14151621
- published12 Dec 2025
- disclosed29 Nov 2025
- creditNicholas Tandiono, vk-can
Introduced: 29 Nov 2025
NewCVE-2025-66034 (opens in a new tab)How to fix?
Upgrade fonttools to version 4.61.0 or higher.
Overview
fonttools is a Tools to manipulate font files
Affected versions of this package are vulnerable to XML Injection via the main() function in the fontTools/varLib/__init__.py file. An attacker can write files to the filesystem by supplying a specially crafted .designspace file.