{"id":"CVE-2026-114134","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-114134","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.","published":"2026-10-22T16:18:57Z","modified":"2026-10-22T16:30:30.132713769Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"PyPI","name":"black","fixedVersion":"26.10.1"}],"fix":{"url":"https://github.com/psf/black/pull/5510","label":"psf/black#5510"},"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"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-22T16:30:30.132713769Z"}}