Medium severity · published Oct 20, 2026
CVE-2026-112915
filelock ReadWriteLock: a crafted lock database makes every acquire stall or hang regardless of timeout
5.5
CVSS
0.2%
EPSS
No
On KEV
Description
filelock is a platform-independent file lock for Python. From 3.20.4 until 4.2.1, ReadWriteLock can open a crafted SQLite lock database without bounding schema and query work, allowing another local user who can replace the database to make acquisition stall or hang; versions from 3.20.4 expose this on initial per-instance opening, and versions from 3.30.0 repeat the exposure on every acquisition. This issue is fixed in version 4.2.1.
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.2% · higher than 12% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
FI
filelock · tox-dev
>= 3.20.4, < 4.2.1 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-112915
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-112915
Patch
https://github.com/tox-dev/filelock/commit/5e3f2ec0c5fb17cb2635b60b2b68bc63ab81ca2d
Patch
https://github.com/tox-dev/filelock/pull/834
Release Notes
https://github.com/tox-dev/filelock/releases/tag/4.2.1
Exploit
https://github.com/tox-dev/filelock/security/advisories/GHSA-cwqr-hh33-gh44
More from filelock
7.1
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
6.5
CVE-2025-68146
filelock has TOCTOU race condition that allows symlink attacks during lock file creation
6.3
CVE-2026-112911
filelock: StrictSoftFileLock and SoftReadWriteLock adopt a protocol directory another user created first, losing mutual exclusion
6.1
CVE-2026-112937
filelock: ReadWriteLock on the hard-link route deletes any directory another user renames onto its .filelock-* link directory name
6.1
CVE-2026-112936
filelock: ReadWriteLock follows a symlink at the lock path into SQLite