{"cve":"CVE-2026-22701","nvd":{"published":"2026-01-10T06:15:52.673","modified":"2026-06-17T10:20:15.667","status":"Analyzed","description":"filelock is a platform-independent file lock for Python. Prior to version 3.20.3, a TOCTOU race condition vulnerability exists in the SoftFileLock implementation of the filelock package. An attacker with local filesystem access and permission to create symlinks can exploit a race condition between the permission validation and file creation to cause lock operations to fail or behave unexpectedly. The vulnerability occurs in the _acquire() method between raise_on_not_writable_file() (permission check) and os.open() (file creation). During this race window, an attacker can create a symlink at the lock file path, potentially causing the lock to operate on an unintended target file or leading to denial of service. This issue has been patched in version 3.20.3.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H","score":5.3},"cwes":["CWE-59","CWE-362","CWE-367"],"references":["https://github.com/tox-dev/filelock/commit/255ed068bc85d1ef406e50a135e1459170dd1bf0","https://github.com/tox-dev/filelock/commit/41b42dd2c72aecf7da83dbda5903b8087dddc4d5","https://github.com/tox-dev/filelock/security/advisories/GHSA-qmgc-5h2g-mvrw"],"products":["tox-dev:filelock"],"source":"nvd","synced_at":"2026-10-19T22:19:41.481987139+00:00"},"epss":{"cve":"CVE-2026-22701","score":0.00127,"percentile":0.02309,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-qmgc-5h2g-mvrw","url":"https://osv.dev/vulnerability/GHSA-qmgc-5h2g-mvrw","summary":"filelock Time-of-Check-Time-of-Use (TOCTOU) Symlink Vulnerability in SoftFileLock","modified":"2026-09-10T03:50:33.702580779Z","packages":[{"ecosystem":"PyPI","name":"filelock","purl":"pkg:pypi/filelock","ranges":["<3.20.3"],"fixed":["3.20.3"]}]},{"id":"PYSEC-2026-1374","url":"https://osv.dev/vulnerability/PYSEC-2026-1374","summary":"filelock Time-of-Check-Time-of-Use (TOCTOU) Symlink Vulnerability in SoftFileLock","modified":"2026-07-07T17:47:14.848248670Z","packages":[{"ecosystem":"PyPI","name":"filelock","purl":"pkg:pypi/filelock","ranges":["<3.20.3"],"fixed":["3.20.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}