CVE-2026-112912

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.

CVSS 3.1

2.5CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS

0.2% chance of exploitation in the next 30 days; higher than 11% of CVEs (scores of 2026-10-25)

CWE

CWE-59

Published

2026-10-20

Modified

2026-10-21

Record from

the NVD, synced 2026-10-22

Affected

• tox-dev:filelock

References

• https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0a
• https://github.com/tox-dev/filelock/pull/835
• https://github.com/tox-dev/filelock/releases/tag/4.2.1
• https://github.com/tox-dev/filelock/security/advisories/GHSA-9j6q-wvj5-jgjg
• https://github.com/tox-dev/filelock/security/advisories/GHSA-9j6q-wvj5-jgjg

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