skia-python vendors vulnerable libfreetype because of pinned cibuildwheel versionGHSA-2mhw-8qcg-gr96
HIGHGHSA-2mhw-8qcg-gr96 is a high-severity (CVSS 8.1) vulnerability in skia-python. A fix is available for skia-python — see the affected versions and patch details below.
Real-World Exposure
skia-python🐍skia-pythonReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Impact
The Linux wheels for skia-python vendor a vulnerable version of libfreetype that is affected by CVE-2025-27363 [1].
The root cause is a chain of unfortunate events:
-
skia-python builds wheels using pinned pypa/[email protected] [2]
-
cibuildwheel 2.21.3 in turn pins manylinux container images [3]
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In these images, version 2.9.1-9.el8 of RedHat package freetype is preinstalled. This package version is vulnerable and has since been patched in 2.9.1-10.
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During the skia-python Linux build, libfreetype is vendored from the system, resulting in skia-python.libs/libfreetype-29a7443c.so.6.16.1
[ To find the provenance of your vendored libfreetype, we extracted the 8-character hash of the original binary file that is added during the build process (29a7443c), and matched it against our database of hashes all historic Red Hat, Debian and Ubuntu releases of freetype. ]
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Because freetype is only a transitive dependency of the packages explicitly installed by the build script [4], it is not upgraded to the patched version [4].
-
As a result, the published wheels embed a vulnerable libfreetype, even though patched packages are available upstream.
This appears to be a broader manylinux ecosystem issue. The base images
do not enforce that yum update runs on container start, so
preinstalled libraries may remain vulnerable indefinitely.
Patches
In the case of skia-python, the solution is to explicitly install freetype in the build process and rebuild the wheels.
The original report was suggesting the above, but in the current build_Linux.sh script, the patched freetype-devel version 2.9.1-10 gets installed as a dependency. It's just that we need to rebuild the wheel for a new release.
Workarounds
Users must upgrade the wheel package after release.
References
- https://nvd.nist.gov/vuln/detail/CVE-2025-27363
- https://github.com/kyamagu/skia-python/blob/9ffb045811f9b5508e152302d5b81aadca6edd8d/.github/workflows/ci.yml#L38
- https://github.com/pypa/cibuildwheel/blob/v2.21.3/cibuildwheel/resources/pinned_docker_images.cfg
- https://github.com/kyamagu/skia-python/blob/9ffb045811f9b5508e152302d5b81aadca6edd8d/scripts/build_Linux.sh#L6
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | skia-python | all versions | No fix |
| 🐍PyPI | skia-python | all versions | 144.0.post1pip install --upgrade 'skia-python==144.0.post1' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for skia-python, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
A fix is available for GHSA-2mhw-8qcg-gr96; check the affected-versions list above or the advisory for the patched release of skia-python, then make sure no transitive dependency still pins the vulnerable range.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is GHSA-2mhw-8qcg-gr96 in your dependencies?
Find it across PyPI, including transitive dependencies.