Moderate severityNVD Advisory· Published Nov 29, 2025· Updated Dec 1, 2025
fontTools is Vulnerable to Arbitrary File Write and XML injection in fontTools.varLib
CVE-2025-66034
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.
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Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
fonttoolsPyPI | >= 4.33.0, < 4.60.2 | 4.60.2 |
Affected products
19- osv-coords18 versionspkg:apk/chainguard/mlflowpkg:apk/chainguard/mlflow-bitnamipkg:apk/chainguard/mlflow-iamguarded-compatpkg:apk/chainguard/open-webuipkg:apk/chainguard/tensorflow-cpu-jupyterpkg:apk/chainguard/tensorflow-gpu-jupyterpkg:apk/wolfi/mlflowpkg:apk/wolfi/mlflow-bitnamipkg:apk/wolfi/mlflow-iamguarded-compatpkg:apk/wolfi/open-webuipkg:apk/wolfi/tensorflow-cpu-jupyterpkg:pypi/fonttoolspkg:rpm/opensuse/python-FontTools&distro=openSUSE%20Leap%2015.6pkg:rpm/opensuse/python-FontTools&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/python-FontTools&distro=openSUSE%20Tumbleweedpkg:rpm/suse/python-FontTools&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Package%20Hub%2015%20SP7pkg:rpm/suse/python-FontTools&distro=SUSE%20Linux%20Enterprise%20Server%2016.0pkg:rpm/suse/python-FontTools&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20applications%2016.0
< 3.6.0-r1+ 17 more
- (no CPE)range: < 3.6.0-r1
- (no CPE)range: < 3.6.0-r1
- (no CPE)range: < 3.6.0-r1
- (no CPE)range: < 0.9.2-r0
- (no CPE)range: < 2.20.0-r5
- (no CPE)range: < 2.20.0-r4
- (no CPE)range: < 3.6.0-r1
- (no CPE)range: < 3.6.0-r1
- (no CPE)range: < 3.6.0-r1
- (no CPE)range: < 0.9.2-r0
- (no CPE)range: < 2.20.0-r5
- (no CPE)range: >= 4.33.0, < 4.60.2
- (no CPE)range: < 4.47.2-150600.3.3.1
- (no CPE)range: < 4.53.1-160000.3.1
- (no CPE)range: < 4.61.1-1.1
- (no CPE)range: < 4.47.2-150600.3.3.1
- (no CPE)range: < 4.53.1-160000.3.1
- (no CPE)range: < 4.53.1-160000.3.1
- Range: >= 4.33.0, < 4.60.2
Patches
Vulnerability mechanics
References
4- github.com/advisories/GHSA-768j-98cg-p3fvghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2025-66034ghsaADVISORY
- github.com/fonttools/fonttools/commit/a696d5ba93270d5954f98e7cab5ddca8a02c1e32ghsax_refsource_MISCWEB
- github.com/fonttools/fonttools/security/advisories/GHSA-768j-98cg-p3fvghsax_refsource_CONFIRMWEB
News mentions
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