Description
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.
Published: 2026-11-05
Score: 5.3 Medium
EPSS: < 1% Very Low
KEV: No
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

Additional remediation guidance may be available on OpenCVE Cloud.

Tracking

Sign in to view the affected projects.

Advisories
Source ID Title
Github GHSA Github GHSA GHSA-8mx5-7m5m-r77g filelock: WindowsFileLock ignores mode: a 0o600 lock file and the ReadWriteLock database inherit the directory ACL
History

Fri, 06 Nov 2026 12:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-279
References
Metrics threat_severity

None

threat_severity

Moderate


Fri, 06 Nov 2026 00:15:00 +0000

Type Values Removed Values Added
First Time appeared Tox-dev
Tox-dev filelock
Vendors & Products Tox-dev
Tox-dev filelock

Thu, 05 Nov 2026 22:00:00 +0000

Type Values Removed Values Added
Description 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.
Title filelock: WindowsFileLock ignores mode: a 0o600 lock file and the ReadWriteLock database inherit the directory ACL
Weaknesses CWE-732
References
Metrics cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L'}


Subscriptions

Tox-dev Filelock
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-11-05T21:47:35.134Z

Reserved: 2026-10-19T20:16:09.857Z

Link: CVE-2026-112910

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-11-05T22:17:46.877

Modified: 2026-11-05T22:17:46.877

Link: CVE-2026-112910

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-11-05T21:47:35Z

Links: CVE-2026-112910 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-11-06T00:00:19Z

Weaknesses
  • CWE-279

    Incorrect Execution-Assigned Permissions

  • CWE-732

    Incorrect Permission Assignment for Critical Resource