{"id":"GHSA-cg8m-r9f2-5wm2","summary":"Black: GitHub Action installs unvalidated required-version from pyproject.toml","details":"### Summary\n\nThe 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.\n\n### Details\n\nThis 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.\n\n### Proof of concept\n\nReproduction 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.\n\n### Impact\n\nThis is a remote code execution vulnerability impacting users using the GitHub Action bundled with psf/black and using the `use_pyproject: true` setting.","aliases":["CVE-2026-114134"],"modified":"2026-10-22T16:30:30.132713769Z","published":"2026-10-22T16:18:57Z","database_specific":{"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-10-22T16:18:57Z","nvd_published_at":null,"cwe_ids":["CWE-829"]},"references":[{"type":"WEB","url":"https://github.com/psf/black/security/advisories/GHSA-cg8m-r9f2-5wm2"},{"type":"WEB","url":"https://github.com/psf/black/pull/5510"},{"type":"WEB","url":"https://github.com/psf/black/commit/ac1f71563aeccf73cf13ece00f231d9d6c66a514"},{"type":"PACKAGE","url":"https://github.com/psf/black"},{"type":"WEB","url":"https://github.com/psf/black/releases/tag/26.10.1"}],"affected":[{"package":{"name":"black","ecosystem":"PyPI","purl":"pkg:pypi/black"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"26.10.1"}]}],"versions":["18.3a0","18.3a1","18.3a2","18.3a3","18.3a4","18.4a0","18.4a1","18.4a2","18.4a3","18.4a4","18.5b0","18.5b1","18.6b0","18.6b1","18.6b2","18.6b3","18.6b4","18.9b0","19.10b0","19.3b0","20.8b0","20.8b1","21.10b0","21.11b0","21.11b1","21.12b0","21.4b0","21.4b1","21.4b2","21.5b0","21.5b1","21.5b2","21.6b0","21.7b0","21.8b0","21.9b0","22.1.0","22.10.0","22.12.0","22.3.0","22.6.0","22.8.0","23.1.0","23.10.0","23.10.1","23.11.0","23.12.0","23.12.1","23.1a1","23.3.0","23.7.0","23.9.0","23.9.1","24.1.0","24.1.1","24.10.0","24.1a1","24.2.0","24.3.0","24.4.0","24.4.1","24.4.2","24.8.0","25.1.0","25.11.0","25.12.0","25.9.0","26.1.0","26.10.0","26.1a1","26.3.0","26.3.1","26.5.0","26.5.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-cg8m-r9f2-5wm2/GHSA-cg8m-r9f2-5wm2.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"}]}