HIGHCVSS not yet scoredVulnerability

CVE-2026-114134

### Summary The GitHub Action bundled with Black can read the version from `tool.black.required-version` if `use_pyproject` is set to True. This version is not validated and therefore can be used to execute untrusted code in the context of a victim's repository. ### Details This is similar to the previous CVE-2026-31900. The value in `tool.black.required-version` is accepted as the version to be installed by the action without validation. ### Proof of concept Reproduction requires a victim to use Black's GitHub Action with `use_pyproject: true`. The attacker would then issue a PR to the victim's repository with `pyproject.toml` edited so that Black points to a malicious repository. ### Impact This is a remote code execution vulnerability impacting users using the GitHub Action bundled with psf/black and using the `use_pyproject: true` setting.

Properties

Ghsa id
GHSA-cg8m-r9f2-5wm2
Summary
Black: GitHub Action installs unvalidated required-version from pyproject.toml
Severity
high
Last source
GitHub Advisory Database
Cve id
CVE-2026-114134
First seen by Signal
2026-10-22T18:12:38+00:00
Is ghsa only
false
Retrieved at
2026-10-22T22:16:44+00:00
Ghsa published
2026-10-22T16:18:57Z
Source url
https://github.com/advisories/GHSA-cg8m-r9f2-5wm2
Ghsa updated
2026-10-22T16:18:58Z

Related Entities (3)

AFFECTS (1)

→[Software]pip/black

VULNERABLE_TO (1)

←[Software]pip/black

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CVE-2026-114134 — Ninja Signal Threat Intelligence | Ninja Signal