filelock: ReadWriteLock on Windows acts on SQLite side files another local user places beside its database
- Exploited
- No known exploitation
- Fix
- Fixed in 4.2.1
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 4.2.1.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 23/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The filelock Python library on Windows is affected through its ReadWriteLock and AsyncReadWriteLock classes. A local user with low privileges, and no action from the victim, can plant SQLite side files beside the lock database in a directory other accounts can write to, which makes every lock acquisition fail immediately regardless of timeout and can cause a file to be deleted when the lock account has permission to delete it.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
filelock is a platform-independent file lock for Python. From 3.20.4 until 4.2.1, ReadWriteLock and AsyncReadWriteLock on Windows use _connect to attach SQLite to the lock database by pathname, allowing another local account that can create adjacent names to place a database-wal or database-journal side file before acquisition. An undeletable WAL file makes each read or write acquisition fail immediately with sqlite3.OperationalError regardless of timeout. Separately, when the database contains at least one table, a hot journal that grants the lock account modify rights can cause SQLite recovery to delete a file named by that journal only when the lock account has permission to delete the target. The issue requires a directory writable by another account, such as a shared Windows temporary directory, and does not affect private directories. This issue is fixed in version 4.2.1.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure?/25Unknown. No advisory context yet
- Reach20/20filelock: 138.8M downloads a week
- Severity3.3/10CVSS 3.3
- No patch0/5No signal
What would change the score
- Would score about 78 if added to CISA KEV
- Would score about 73 if CISA's SSVC rates exploitation active
- Would score about 45 if advisories confirm default setups are exposed
Impact
- Widely used
filelock has 138.8m weekly downloads.Source: pypistats.org
47.2k packages depend on filelock.Source: deps.dev
What to do
Upgrade to a fixed version: 4.2.1.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- tox-dev filelock
From 3.20.4 · fixed in 4.2.1
- filelockPyPI
From 3.20.4 · fixed in 4.2.1
Evidence 5
- Advisory
- Repository
- Repository
- Repository
- Repository
Corrections
None so far.
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Questions about CVE-2026-112913
Is CVE-2026-112913 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-112913?
filelock: from 3.20.4 before 4.2.1. filelock (PyPI): from 3.20.4 before 4.2.1.Source: cve.now feed data
How do I fix CVE-2026-112913?
Upgrade to a fixed version: 4.2.1.Source: cve.now feed data