CVE-2026-112912

Name	CVE-2026-112912
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
python-filelock (PTS)	bookworm	3.9.0-1+deb12u1	vulnerable
	trixie	3.18.0-1+deb13u1	vulnerable
	forky, sid	4.1.1-1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
python-filelock	source	(unstable)	(unfixed)

Notes

https://github.com/tox-dev/filelock/security/advisories/GHSA-9j6q-wvj5-jgjg
https://github.com/tox-dev/filelock/pull/835
Fixed by: https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0a (4.2.1)