CVE-2026-112940 filelock ReadWriteLock: SQLite reopens the lock database by name, so a planted symlink or journal file makes the lock user's process overwrite or unlink its own files
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-112940?
CVE-2026-112940 is a high-severity vulnerability in tox-dev filelock, published on 20 Oct 2026.
Official 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.
Which versions are affected by CVE-2026-112940?
2 open source packages ship an affected version, including filelock. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
filelock PyPI | From 3.20.4 | 4.2.1 |
filelock PyPI | From 3.20.4 | 4.2.1 |
Products include Tox-Dev Filelock.
How do I fix CVE-2026-112940?
Upgrade filelock to 4.2.1 or later.
Is CVE-2026-112940 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112940 exists.
Other vulnerabilities in tox-dev filelock
- CVE-2026-112911 filelock: StrictSoftFileLock and SoftReadWriteLock adopt a protocol directory another user created first, losing mutual exclusion
- CVE-2025-68146 filelock has TOCTOU race condition that allows symlink attacks during lock file creation
- CVE-2026-112909 filelock: UnixFileLock truncates and chmods any regular file another user renames or hard-links onto the lock path
- CVE-2026-112934 filelock: SoftReadWriteLock holder refresh writes through a hard link and hangs on a named pipe that another local user renames over its record
- CVE-2026-112936 filelock: ReadWriteLock follows a symlink at the lock path into SQLite
Sources
Also known as CLEANSTART-2026-AE20147, DEBIAN-CVE-2026-112940, ECHO-a690-810d-47b0, GHSA-v4x8-3wr5-3wq8, MINI-qfrg-8m9x-cc2v, ROOT-APP-PYPI-CVE-2026-112940 and 1 more.