CVE-2026-112940

Name	CVE-2026-112940
Description	filelock is a platform-independent file lock for Python. From 3.20.4 until 4.2.1, ReadWriteLock let SQLite reopen the database and side files by name; on POSIX systems an attacker with rename access in a non-sticky parent can swap those names to cause overwrite or unlink operations, while a writable adjacent hot journal is additionally required for attacker-chosen content overwrites. 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	4.0.1-1	vulnerable
	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-v4x8-3wr5-3wq8
https://github.com/tox-dev/filelock/pull/834
Fixed by: https://github.com/tox-dev/filelock/commit/5e3f2ec0c5fb17cb2635b60b2b68bc63ab81ca2d (4.2.1)