filelock: SoftFileLock stale-break restore follows a swapped-in symbolic link and hard-links a file of the user running the lock into the lock directory

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-112914
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-20 15:17:15 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, SoftFileLock can restore a stale marker by name after moving it aside, allowing another local user with rename access in a non-sticky lock directory to swap in a symbolic link and, on a runtime that follows the link and a same-filesystem target, make the lock user hard-link one of its files into the lock directory. This issue is fixed in version 4.2.1.

Risk And Classification

Primary CVSS: v3.1 5.3 MEDIUM from [email protected]

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

Problem Types: CWE-363 | CWE-363 CWE-363: Race Condition Enabling Link Following

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N
3.1CNADECLARED5.3MEDIUMCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N

CVSS v3.1 Breakdown

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

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/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/releases/tag/4.2.1 [email protected] github.com
github.com/tox-dev/filelock/pull/843 [email protected] github.com
github.com/tox-dev/filelock/commit/740ff666b62a88496c8d7394e4e6230605e4d62b [email protected] github.com
github.com/tox-dev/filelock/security/advisories/GHSA-crv4-6mhj-j5jh [email protected] github.com
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