gam · filelock: ReadWriteLock on the hard-link route deletes any directory another user renames onto its .filelock-* link
Affects gamSource GCVE Database
Not known to be exploited · CVSS 6.1 Medium.
Data as of 9 Nov 2026, 20:04 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:LExploitation evidence
Disclosed: evidence found.
CVE published 20 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 9 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewgampkg:brew/gamOther 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
Users should upgrade filelock to a version later than 4.2.0 once available, as affected versions are 4.1.0 through 4.2.0. Until a patch is confirmed, ensure that directories containing the lock database are not writable by other users and have the sticky bit set to prevent unauthorized renames. Avoid running lock users in environments where /proc/self/fd is unavailable or hidden. Restrict write permissions on shared parent directories to trusted users only.
Description
A vulnerability in the filelock Python package versions 4.1.0 through 4.2.0 allows a local user with write permission on the directory containing the lock database to rename directories in a way that causes the lock user's process to recursively delete arbitrary directories. This occurs because the ReadWriteLock and AsyncReadWriteLock implementations remove their private .filelock-* link directories without verifying that the path still points to the originally created directory. The issue affects macOS since version 4.1.1 and POSIX environments without a usable /proc/self/fd, such as chroot or containers without /proc mounted. The vulnerability requires a non-sticky, writable shared parent directory and allows deletion of directories owned by the lock user, resulting in integrity and partial availability loss. The CVSS 3.1 score is 6.1 (Medium).
References
- github.com/tox-dev/filelock/security/advisories/GHSA-jqc4-5cvw-7w85 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-112937 (opens in a new tab)
- github.com/tox-dev/filelock/pull/834 (opens in a new tab)
- github.com/tox-dev/filelock/commit/5e3f2ec0c5fb17cb2635b60b2b68bc63ab81ca2d (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)