How severe is GHSA-v53h-f6m7-xcgm?

No CVSS score has been assigned to GHSA-v53h-f6m7-xcgm yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by GHSA-v53h-f6m7-xcgm?

GHSA-v53h-f6m7-xcgm affects the following packages: psf/black (GitHub Actions). Ecosystems affected: GitHub Actions.

How do I fix GHSA-v53h-f6m7-xcgm?

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.

How do I detect GHSA-v53h-f6m7-xcgm in my GitHub Actions dependencies?

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.

How do I mitigate GHSA-v53h-f6m7-xcgm if there is no patch (or I can't update yet)?

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.

Is GHSA-v53h-f6m7-xcgm actively exploited in the wild?

No public exploit code has been indexed for GHSA-v53h-f6m7-xcgm yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-v53h-f6m7-xcgm?

GHSA-v53h-f6m7-xcgm has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 45th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-v53h-f6m7-xcgm?

GHSA-v53h-f6m7-xcgm is classified as Improper Input Validation (CWE-20). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-v53h-f6m7-xcgm published, and has it been updated?

GHSA-v53h-f6m7-xcgm was published on March 7, 2026 and was last updated on July 13, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 GitHub Actions

Not in CISA KEV

Black's vulnerable version parsing leads to RCE in GitHub ActionGHSA-v53h-f6m7-xcgm

Fix: psf/black@0a2560b

GHSA-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.

Also known asCVE-2026-31900PYSEC-2026-2120

Published

Mar 7, 2026

Updated

Jul 13, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

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

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk+0.03%

Lower risk than most CVEs45th percentile — riskier than 45% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

📦psf/black

Real-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

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦GitHub Actions	`psf/black`	all versions	26.3.0

Affected Products

1 product · 1 configurations

Application

blackpython

< 26.3.0

range

Detection & mitigation playbook

Open-source dependency

Detect
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.

Frequently Asked Questions

### Impact Black provides a [GitHub action](https://black.readthedocs.io/en/stable/integrations/github_actions.html) 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

O3 Security · Impact-Aware SCA

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