lexicon · filelock: StrictSoftFileLock creates its claim directories without the lock mode, so another local user with a write
Affects lexiconSource GCVE Database
Not known to be exploited · CVSS 5.3 Medium : upgrade to 3.25.2_5 when convenient.
Data as of 30 Oct 2026, 07:32 UTC
- Patch
- Available – fixed in 3.25.2_5
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:LExploitation evidence
Disclosed: evidence found.
CVE published 29 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.
What to do
Upgrade lexicon to 3.25.2_5.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewlexiconpkg:brew/lexiconOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available in filelock version 3.25.2_5 that addresses this issue. Users should upgrade to this fixed version. Additionally, existing claim directories created by affected versions may retain insecure permissions; these directories should be removed or have their permissions corrected (e.g., via chmod) to prevent exploitation. No other actions are required if the patch is applied.
Description
The filelock library versions 3.30.0 through 4.2.0 have a vulnerability in the StrictSoftFileLock and AsyncStrictSoftFileLock classes where claim directories are created without proper restrictive permissions. This allows another local user with write access to the directory to unlink claim files, causing multiple holders to believe they hold the lock simultaneously. The issue arises when the environment's umask or default ACLs permit write access to these directories. The vulnerability impacts integrity by allowing concurrent writes protected by the lock, with no confidentiality or significant availability impact.
References
- github.com/tox-dev/filelock/security/advisories/GHSA-6627-m3xw-93mp (opens in a new tab)
- github.com/tox-dev/filelock/pull/839 (opens in a new tab)
- github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03 (opens in a new tab)
- github.com/tox-dev/filelock (opens in a new tab)
- github.com/tox-dev/filelock/releases/tag/4.2.1 (opens in a new tab)