GHSA-3936-CMFR-PM3M

Vulnerability from github – Published: 2026-03-12 18:33 – Updated: 2026-03-13 13:36
VLAI?
Summary
Black: Arbitrary file writes from unsanitized user input in cache file name
Details

Impact

Black writes a cache file, the name of which is computed from various formatting options. The value of the --python-cell-magics option was placed in the filename without sanitization, which allowed an attacker who controls the value of this argument to write cache files to arbitrary file system locations.

Patches

Fixed in Black 26.3.1.

Workarounds

Do not allow untrusted user input into the value of the --python-cell-magics option.

Severity ?
8.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "black"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "26.3.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-32274"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-12T18:33:10Z",
    "nvd_published_at": "2026-03-12T20:16:06Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nBlack writes a cache file, the name of which is computed from various formatting options. The value of the `--python-cell-magics` option was placed in the filename without sanitization, which allowed an attacker who controls the value of this argument to write cache files to arbitrary file system locations. \n\n### Patches\n\nFixed in Black 26.3.1.\n\n### Workarounds\n\nDo not allow untrusted user input into the value of the `--python-cell-magics` option.",
  "id": "GHSA-3936-cmfr-pm3m",
  "modified": "2026-03-13T13:36:21Z",
  "published": "2026-03-12T18:33:10Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/psf/black/security/advisories/GHSA-3936-cmfr-pm3m"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-32274"
    },
    {
      "type": "WEB",
      "url": "https://github.com/psf/black/pull/5038"
    },
    {
      "type": "WEB",
      "url": "https://github.com/psf/black/commit/4937fe6cf241139ddbfc16b0bdbb5b422798909d"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/psf/black"
    },
    {
      "type": "WEB",
      "url": "https://github.com/psf/black/releases/tag/26.3.1"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Black: Arbitrary file writes from unsanitized user input in cache file name"
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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