gam · filelock: SoftFileLock stale-break restore follows a swapped-in symbolic link and hard-links a file of the user
Affects gamSource GCVE Database
Not known to be exploited · CVSS 5.3 Medium.
Data as of 9 Nov 2026, 20:05 UTC
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:NExploitation 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
The vulnerability is conditional on the lock directory being writable by the attacker and lacking the sticky bit. Using directories with the sticky bit set (e.g., mode 1777) or ensuring the directory and its ancestors are owned by the lock user or root and not writable by others prevents exploitation. On Linux, enabling fs.protected_symlinks=1 also prevents following symbolic links in world-writable sticky directories. Upgrading filelock beyond version 4.2.0 is recommended if a fix is available. Patch status is not explicitly stated; check vendor advisories for updates. Avoid running on CPython 3.12 or later on affected platforms if possible until patched.
Description
A vulnerability in filelock versions 4.1.0 through 4.2.0 allows a local unprivileged user to exploit a race condition in the SoftFileLock stale-break restore process. By replacing a lock file marker with a symbolic link in a writable, non-sticky shared directory, the attacker can cause the lock user to create a hard link to one of their own files. This exposes file metadata and allows the attacker to manipulate the file's name. On version 4.2.0, this can lead to truncation of the file by the lock user's subsequent FileLock operation. The vulnerability requires specific conditions including a writable non-sticky directory and CPython 3.12 or later on Linux/macOS.
References
- github.com/tox-dev/filelock/security/advisories/GHSA-crv4-6mhj-j5jh (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-112914 (opens in a new tab)
- github.com/tox-dev/filelock/pull/843 (opens in a new tab)
- github.com/tox-dev/filelock/commit/740ff666b62a88496c8d7394e4e6230605e4d62b (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)