PYSEC-2026-2120

Vulnerability from pysec - Published: 2026-03-11 20:16 - Updated: 2026-07-13 05:48
VLAI
Details

Black is the uncompromising Python code formatter. 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. Version 26.3.0 fixes this vulnerability.

Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Impacted products
Name purl
black pkg:pypi/black
Aliases
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {},
      "package": {
        "ecosystem": "PyPI",
        "name": "black",
        "purl": "pkg:pypi/black"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "26.3.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "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",
        "26.1a1"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-31900",
    "GHSA-v53h-f6m7-xcgm"
  ],
  "details": "Black is the uncompromising Python code formatter. 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. Version 26.3.0 fixes this vulnerability.",
  "id": "PYSEC-2026-2120",
  "modified": "2026-07-13T05:48:07.029632Z",
  "published": "2026-03-11T20:16:15.960Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/psf/black/security/advisories/GHSA-v53h-f6m7-xcgm"
    },
    {
      "type": "FIX",
      "url": "https://github.com/psf/black/commit/0a2560b981364dde4c8cf8ce9d164c40669a8611"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}



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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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