filelock is a platform-independent file lock for Python. From 3.32.6 until 4.2.1, SoftFileLock can follow a swapped symbolic link during the conditional os.access writability check for a node without its owner-write bit, allowing another local user on a platform and directory configuration that follows the link to infer whether a chosen path exists and is writable from the observable acquisition result. This issue is fixed in version 4.2.1.
Advisories

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Fixes

Solution

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Workaround

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History

Tue, 20 Oct 2026 16:45:00 +0000

Type Values Removed Values Added
First Time appeared Tox-dev
Tox-dev filelock
Vendors & Products Tox-dev
Tox-dev filelock

Tue, 20 Oct 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Tue, 20 Oct 2026 14:45:00 +0000

Type Values Removed Values Added
Description filelock is a platform-independent file lock for Python. From 3.32.6 until 4.2.1, SoftFileLock can follow a swapped symbolic link during the conditional os.access writability check for a node without its owner-write bit, allowing another local user on a platform and directory configuration that follows the link to infer whether a chosen path exists and is writable from the observable acquisition result. This issue is fixed in version 4.2.1.
Title filelock: Symlink swap during SoftFileLock's writability check leaks whether a path exists and is writable by the lock taker
Weaknesses CWE-59
References
Metrics cvssV3_1

{'score': 2.5, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-20T15:37:56.208Z

Reserved: 2026-10-19T20:16:09.858Z

Link: CVE-2026-112912

cve-icon Vulnrichment

Updated: 2026-10-20T15:37:49.246Z

cve-icon NVD

Status : Received

Published: 2026-10-20T15:17:15.657

Modified: 2026-10-20T16:17:04.393

Link: CVE-2026-112912

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-20T16:30:06Z

Weaknesses