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CVE-2026-112909

Full vulnerability record from the local CVENow database.

Description

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.

Severity
MEDIUM
CVSS score
6.1 (v3.1)
Vulnerability status
Analyzed
Source identifier
Published
2026-10-20 15:17:15.313000
Last modified
2026-10-27 21:04:56.090000
View original CVE JSON
{
  "id": "CVE-2026-112909",
  "sourceIdentifier": "[email protected]",
  "published": "2026-10-20T15:17:15.313",
  "lastModified": "2026-10-27T21:04:56.090",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "tox-dev",
          "product": "filelock",
          "versions": [
            {
              "version": "< 4.2.1",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N",
          "baseScore": 6.1,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "LOW",
          "integrityImpact": "HIGH",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 4.2
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-10-22T21:24:59.918929Z",
          "id": "CVE-2026-112909",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-706"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:a:tox-dev:filelock:*:*:*:*:*:python:*:*",
              "versionEndExcluding": "4.2.1",
              "matchCriteriaId": "D16E2F62-8710-4B7F-A294-6F47B5A71249"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0a",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/tox-dev/filelock/pull/835",
      "source": "[email protected]",
      "tags": [
        "Patch"
      ]
    },
    {
      "url": "https://github.com/tox-dev/filelock/releases/tag/4.2.1",
      "source": "[email protected]",
      "tags": [
        "Release Notes"
      ]
    },
    {
      "url": "https://github.com/tox-dev/filelock/security/advisories/GHSA-69hj-f68j-2879",
      "source": "[email protected]",
      "tags": [
        "Exploit",
        "Mitigation",
        "Patch",
        "Vendor Advisory"
      ]
    },
    {
      "url": "https://github.com/tox-dev/filelock/security/advisories/GHSA-69hj-f68j-2879",
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "tags": [
        "Exploit",
        "Mitigation",
        "Patch",
        "Vendor Advisory"
      ]
    }
  ]
}