GHSA-v53h-f6m7-xcgm — psf/black
Fix: psf/black@0a2560bGHSA-v53h-f6m7-xcgm is a Improper Input Validation vulnerability in psf/black. A fix is available for psf/black — see the affected versions and patch details below.
Black's vulnerable version parsing leads to RCE in GitHub Action
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-v53h-f6m7-xcgm.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Real-World Exposure
psf/blackReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects GitHub Actions packages — download data is not available via public APIs for these ecosystems.
Description
Impact
Black provides a GitHub action for formatting code. This action supports an option, use_pyproject: true, for reading the version of Black to use from the repository pyproject.toml. A malicious pull request could edit pyproject.toml to use a direct URL reference to a malicious repository. This could lead to arbitrary code execution in the context of the GitHub Action. Attackers could then gain access to secrets or permissions available in the context of the action.
Patches
Version 26.3.0 fixes this vulnerability by tightening the validation of the version field. Users who use the GitHub Action as psf/black@stable will automatically pick up this update.
Workarounds
Do not use the use_pyproject: true option in the psf/black GitHub Action.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦GitHub Actions | psf/black | all versions | 26.3.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for psf/black, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update psf/black to 26.3.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v53h-f6m7-xcgm is resolved across your whole dependency graph.
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.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-v53h-f6m7-xcgm can be triaged on real exposure rather than presence alone.
Tailored to GHSA-v53h-f6m7-xcgm. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-v53h-f6m7-xcgm in your dependencies?
O3 Security finds GHSA-v53h-f6m7-xcgm across GitHub Actions dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.