TI-2026-18228 Aliases CVE-2026-22701 GHSA-qmgc-5h2g-mvrw

filelock Time-of-Check-Time-of-Use (TOCTOU) Symlink Vulnerability in SoftFileLock

LOW 23CWE-362Published 2026-01-10 · Updated 2026-01-12

Key facts

Attack vector: Local
Privileges required: Low
User interaction: None
Attack complexity: High
Impact type: —
Confidentiality · integrity · availability: None · Low · High
Fix status: Partial Red Hat: 13 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat.

Summary

filelock is a platform-independent file lock for Python. Prior to version 3.20.3, a TOCTOU race condition vulnerability exists in the SoftFileLock implementation of the filelock package. An attacker with local filesystem access and permission to create symlinks can exploit a race condition between the permission validation and file creation to cause lock operations to fail or behave unexpectedly. The vulnerability occurs in the _acquire() method between raise_on_not_writable_file() (permission check) and os.open() (file creation). During this race window, an attacker can create a symlink at the lock file path, potentially causing the lock to operate on an unintended target file or leading to denial of service. This issue has been patched in version 3.20.3.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00127 2nd percentileScored 2026-11-07

Fix Partial filelock (tox-dev): 3.20.3filelock (PyPI): 3.20.3Red Hat: 13 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
tox-dev	filelock	before 3.20.3	3.20.3	Patch available	CNA
—	filelock (PyPI)	before 3.20.3	3.20.3	Patch available	GHSA-qmgc-5h2g-mvrw

filelock Vendortox-dev Affected before 3.20.3 Fixed in 3.20.3 Patch available CNA
filelock (PyPI) Vendor— Affected before 3.20.3 Fixed in 3.20.3 Patch available GHSA-qmgc-5h2g-mvrw

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:tox-dev:filelock::::::python::*	before 3.20.3	Vulnerable	tox-dev

cpe:2.3:a:tox-dev:filelock:*:*:*:*:*:python:*:* Versions before 3.20.3 Vulnerable ·tox-dev

Remediation

Fix · CNA filelock (tox-dev) Fixed in 3.20.3
Fix · GHSA-qmgc-5h2g-mvrw filelock (PyPI) Fixed in 3.20.3 Advisory →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Migration Toolkit for Containers	Affected	No fix yet: Fix deferred
OpenShift Lightspeed	Affected	No fix yet: Fix deferred
OpenShift Service Mesh 2	Affected	No fix yet: Fix deferred
Red Hat AI Inference Server	Affected	No fix yet: Fix deferred
Red Hat Ansible Automation Platform 2	Affected	No fix yet: Fix deferred
Red Hat Ansible Automation Platform Ansible Core 2	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux AI (RHEL AI) 3	Affected	No fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)	Affected	No fix yet: Fix deferred
Red Hat OpenShift Container Platform 4	Affected	No fix yet: Fix deferred
Red Hat OpenShift Dev Spaces	Affected	No fix yet: Fix deferred
Red Hat OpenStack Platform 18.0	Affected	No fix yet: Fix deferred
Red Hat Satellite 6	Affected	No fix yet: Fix deferred
Red Hat Trusted Artifact Signer	Affected	No fix yet: Fix deferred

Timeline

2026-10-02 Threatist record created from CVE-2026-22701
2026-10-03 Alias added: GHSA-qmgc-5h2g-mvrw

References

Patch 3

Advisory 1

https://nvd.nist.gov/vuln/detail/CVE-2026-22701

Other 1

https://github.com/tox-dev/filelock

TI-2026-76862 Symlink race in filelock ReadWriteLock lets attackers overwrite files CVSS 3.1HIGH 7.1
TI-2026-76853 filelock soft locks adopt directories created by other local users CVSS 3.1MEDIUM 6.3
TI-2026-76859 Symlink following in filelock ReadWriteLock redirects SQLite database CVSS 3.1MEDIUM 6.1
TI-2026-76857 Unsafe holder record refresh in filelock SoftReadWriteLock CVSS 3.1MEDIUM 6.1
TI-2026-76852 filelock UnixFileLock truncates files placed on the lock path CVSS 3.1MEDIUM 6.1
TI-2026-76856 Crafted lock database makes filelock ReadWriteLock acquisitions hang CVSS 3.1MEDIUM 5.5

See all 14 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences