Black: Arbitrary file writes from unsanitized user input in cache file name

{
  "id": "30de03a406979e5d58a6fc2ed3f1a480db091f58db1dd51ed1fd8dc2c60bbfd1",
  "url": "https://osv.dev/vulnerability/CVE-2026-32274",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Black: Arbitrary file writes from unsanitized user input in cache file name",
    "summary": "Black is the uncompromising Python code formatter. Starting in version 24.3.0 and prior to version 26.3.1, 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. Fixed in Black 26.3.1.",
    "evidence": "osv:CVE-2026-32274",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-32274",
      "aliases": [
        "CVE-2026-32274",
        "GHSA-3936-cmfr-pm3m",
        "PYSEC-2026-2121"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/psf/black",
              "type": "GIT",
              "events": [
                {
                  "introduced": "552baf822992936134cbd31a38f69c8cfe7c0f05"
                },
                {
                  "fixed": "c6755bb741b6481d6b3d3bb563c83fa060db96c9"
                },
                {
                  "fixed": "4937fe6cf241139ddbfc16b0bdbb5b422798909d"
                },
                {
                  "fixed": "ed770ba4dd50c419148a0fca2b43937a7447e1f9"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "24.3.0"
                      },
                      {
                        "fixed": "26.3.1"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "4937fe6cf241139ddbfc16b0bdbb5b422798909d"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "ed770ba4dd50c419148a0fca2b43937a7447e1f9"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "c6755bb741b6481d6b3d3bb563c83fa060db96c9"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "26.3.1"
                  }
                ]
              }
            }
          ],
          "versions": [
            "26.3.0",
            "26.1.0",
            "25.12.0",
            "25.11.0",
            "25.9.0",
            "25.1.0",
            "24.10.0",
            "24.8.0",
            "24.4.2",
            "24.4.1",
            "24.4.0",
            "24.3.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-32274.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:41.597341815Z",
      "provider": "osv",
      "references": [
        "https://access.redhat.com/security/cve/CVE-2026-32274",
        "https://github.com/psf/black/releases/tag/26.3.1",
        "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32274.json",
        "https://access.redhat.com/errata/RHSA-2026:10184",
        "https://access.redhat.com/errata/RHSA-2026:13545",
        "https://access.redhat.com/errata/RHSA-2026:13553",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32274.json",
        "https://github.com/psf/black/security/advisories/GHSA-3936-cmfr-pm3m",
        "https://github.com/pypa/advisory-database/tree/main/vulns/black/PYSEC-2026-2121.yaml",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-32274",
        "https://bugzilla.redhat.com/show_bug.cgi?id=2447111",
        "https://github.com/psf/black/commit/4937fe6cf241139ddbfc16b0bdbb5b422798909d",
        "https://github.com/psf/black/commit/ed770ba4dd50c419148a0fca2b43937a7447e1f9",
        "https://github.com/psf/black/pull/4176",
        "https://github.com/psf/black/pull/5038"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/32xxx/CVE-2026-32274.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-32274",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 509016,
  "published_at": "2026-03-12T19:47:07.464+00:00"
}