CVE-2026-112910

MEDIUM 5.3

filelock: WindowsFileLock ignores mode: a 0o600 lock file and the ReadWriteLock database inherit the directory ACL

CVSS Score

5.3

EPSS Score

0.0%

EPSS Percentile

0th

filelock is a platform-independent file lock for Python. From 3.10.0 until 4.2.1, filelock on Windows ignores the mode argument for WindowsFileLock files and the ReadWriteLock SQLite database. A lock created with mode=0o600 receives the parent directory's inheritable ACL because _open_non_reparse_fd and _nt_open do not create an owner-only security descriptor. Another local account with inherited access can read holder metadata or the lock database, modify those files where the ACL permits writes, or take the byte-range lock after release and delay later acquisitions. UnixFileLock is not affected, and mutual exclusion between cooperating processes continues to hold. This issue is fixed in version 4.2.1.

CWE	CWE-732
Vendor	tox-dev
Product	filelock
Published	Nov 5, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

Low

Affected Versions

tox-dev / filelock

>= 3.10.0, < 4.2.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/tox-dev/filelock/security/advisories/GHSA-8mx5-7m5m-r77g github.com: https://github.com/tox-dev/filelock/pull/835 github.com: https://github.com/tox-dev/filelock/commit/72786d41aa25159ad28c1bcf4291738b135b2c6c github.com: https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0a github.com: https://github.com/tox-dev/filelock/releases/tag/4.2.1