gam · filelock ReadWriteLock: SQLite reopens the lock database by name, so a planted symlink or journal file makes the lock
Affects gamSource GCVE Database
Not known to be exploited · CVSS 7.1 High.
Data as of 9 Nov 2026, 20:03 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 7.1 |
|---|
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:HExploitation 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
Mitigation involves ensuring that directories containing the lock database are not writable by untrusted local users and have the sticky bit set to prevent unauthorized file renaming or creation. Kernel settings such as fs.protected_regular and fs.protected_hardlinks should be enabled (default on most distributions) to reduce exploitability. Avoid using filelock in shared writable directories without proper permissions. Monitor vendor advisories for any official patches or updates.
Description
The ReadWriteLock and AsyncReadWriteLock components of filelock use SQLite databases for locking, but on Linux, SQLite reopens the lock database by name, following symlinks and acting on side files such as -journal, -wal, and -shm. This behavior allows a local attacker with write permissions in the directory containing the lock database to manipulate these files, causing the lock user to write arbitrary data into their own files, create or unlink files, or cause lock acquisition failures. The vulnerability affects filelock versions 3.20.4 through 4.2.0, with the /proc/self/fd redirect introduced in 4.0.9 and side-file variants since 3.20.4. The CVSS 3.1 score is 7.1 (High), reflecting local attack complexity but high integrity and availability impact. The issue requires a writable, non-sticky directory accessible to the attacker. In sticky directories like /tmp, a planted -wal file causes lock acquisition failures. Kernel settings such as fs.protected_regular and fs.protected_hardlinks influence the exploitability. No confidentiality impact is noted.
References
- github.com/tox-dev/filelock/security/advisories/GHSA-v4x8-3wr5-3wq8 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-112940 (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)