CVE-2025-68146: Lexicon · filelock has a TOCTOU race condition which allows symlink attacks during lock file creation
Affects lexiconSource GCVE Database
Not known to be exploited · CVSS 6.3 Medium : upgrade to 3.23.2_2 when convenient.
Data as of 30 Oct 2026, 07:45 UTC
- Patch
- Available – fixed in 3.23.2_2
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 16 Dec 2025
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 3.23.2_2.
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 3.20.1 that fixes the vulnerability by preventing symlink following during lock file creation. Users should upgrade to filelock 3.20.1 or later immediately. If upgrading is not possible, partial mitigations include using SoftFileLock instead of UnixFileLock/WindowsFileLock, restricting lock file directory permissions to prevent untrusted symlink creation, and monitoring lock file directories for suspicious symlinks. However, these workarounds do not fully eliminate the race condition and upgrading remains strongly recommended.
Description
CVE-2025-68146 is a TOCTOU race condition vulnerability in the filelock library affecting Unix, Linux, macOS, and Windows. It allows local attackers with filesystem access to exploit a timing window between checking for a lock file's existence and opening it with truncation flags. By creating a symlink during this window, attackers can cause arbitrary user files to be truncated. This impacts dependent software such as virtualenv, PyTorch, poetry, and tox. The issue is fixed in filelock version 3.20.1 by preventing symlink following during lock file creation.
References
- github.com/tox-dev/filelock/security/advisories/GHSA-w853-jp5j-5j7f (opens in a new tab)
- github.com/tox-dev/filelock/commit/4724d7f8c3393ec1f048c93933e6e3e6ec321f0e (opens in a new tab)
- github.com/tox-dev/filelock (opens in a new tab)
- github.com/tox-dev/filelock/releases/tag/3.20.1 (opens in a new tab)
- learn.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants (opens in a new tab)
- pubs.opengroup.org/onlinepubs/9699919799/functions/open.html (opens in a new tab)