filelock: SoftReadWriteLock follows a lock tree swapped in after its first acquire and writes lock records into directories of the user running the lock

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-112941
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-20 15:17:16 UTC
Updated2026-10-20 19:50:26 UTC
Descriptionfilelock is a platform-independent file lock for Python. From 4.1.0 until 4.2.1, SoftReadWriteLock and AsyncSoftReadWriteLock cache a successful check of the <path>.rw lock tree and resolve its names again during later record operations, allowing another local user who can replace that tree after the first acquisition to redirect lock-record writes into directories writable by the lock user. This issue is fixed in version 4.2.1.

Risk And Classification

Primary CVSS: v3.1 3.3 LOW from [email protected]

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

Problem Types: CWE-367 | CWE-367 CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary3.3LOWCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
3.1CNADECLARED3.3LOWCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Tox-dev Filelock affected >= 4.1.0, < 4.2.1 Not specified

References

ReferenceSourceLinkTags
github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03 [email protected] github.com
github.com/tox-dev/filelock/releases/tag/4.2.1 [email protected] github.com
github.com/tox-dev/filelock/security/advisories/GHSA-wfhq-q4j2-c37m [email protected] github.com
github.com/tox-dev/filelock/pull/842 [email protected] github.com
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