{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "0"
                  },
                  {
                    "fixed": "4.2.1"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              },
              {
                "range": [
                  {
                    "fixed": "e1e825b1992f69fb6b346dc395d5ae4893536c0a"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "original_tag": "4.2.1",
                "range": [
                  {
                    "fixed": "60331bb89f325020b48bc51bde904c6446384e4a"
                  }
                ],
                "source": "REFERENCES_TAG"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "60331bb89f325020b48bc51bde904c6446384e4a"
            },
            {
              "fixed": "e1e825b1992f69fb6b346dc395d5ae4893536c0a"
            }
          ],
          "repo": "https://github.com/tox-dev/filelock",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-69hj-f68j-2879"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-706"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/112xxx/CVE-2026-112909.json"
  },
  "details": "filelock is a platform-independent file lock for Python. Prior to 4.2.1, UnixFileLock can truncate a regular file renamed onto the lock path when another local user has actual rename permission, or hard-linked there under a permissive hard-link policy; when an explicit mode is requested, affected versions from 3.10.2 can also change that file's mode. This issue is fixed in version 4.2.1.",
  "id": "CVE-2026-112909",
  "modified": "2026-10-22T02:31:06.236689339Z",
  "published": "2026-10-20T14:16:02.317Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/112xxx/CVE-2026-112909.json"
    },
    {
      "type": "FIX",
      "url": "https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0a"
    },
    {
      "type": "FIX",
      "url": "https://github.com/tox-dev/filelock/pull/835"
    },
    {
      "type": "WEB",
      "url": "https://github.com/tox-dev/filelock/releases/tag/4.2.1"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/tox-dev/filelock/security/advisories/GHSA-69hj-f68j-2879"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-112909"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "filelock: UnixFileLock truncates and chmods any regular file another user renames or hard-links onto the lock path"
}