CVE-2026-112909

filelock: UnixFileLock truncates and chmods any regular file another user renames or hard-links onto the lock path

Published Oct 20, 2026 CVSS 3.1 · 6.1 Medium EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-69hj-f68j-2879 filelock: UnixFileLock truncates and chmods any regular file another user renames or hard-links onto the lock path
History
Type Values Removed Values Added
CPEs cpe:2.3:a:tox-dev:filelock:*:*:*:*:*:python:*:*
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Tox-dev
Tox-dev filelock
Vendors & Products Tox-dev
Tox-dev filelock
Type Values Removed Values Added
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.
Title filelock: UnixFileLock truncates and chmods any regular file another user renames or hard-links onto the lock path
Weaknesses CWE-706
References
Metrics cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 22, 2026, 9:25 PM
Reserved
Oct 19, 2026, 8:16 PM
Status
Analyzed
Published
Oct 20, 2026, 3:17 PM
Modified
Oct 27, 2026, 9:04 PM
Severity
Moderate
Public date
Oct 20, 2026, 2:16 PM