hatch · filelock: SoftFileLock removes a live holder's marker when another user forges the PID in a writable marker
Affects hatchSource GCVE Database
Not known to be exploited · CVSS 4.7 Medium : upgrade to 1.18.1_2 when convenient.
Data as of 30 Oct 2026, 09:00 UTC
- Patch
- Available – fixed in 1.18.1_2
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/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 29 Oct 2026.
What to do
Upgrade hatch to 1.18.1_2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewhatchpkg:brew/hatchOther 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 and should be applied to upgrade to version 1.18.1_2 or later, which fixes the vulnerability. Until patched, ensure that lock marker files are not created with group or other write permissions, and avoid permissive umasks (such as 002 or 000) in directories with sticky bits or restricted removal rights. Restrict write permissions on the marker files to prevent unauthorized modification. No other specific mitigations are indicated by the vendor advisory.
Description
A vulnerability in filelock versions 3.22.0 through 4.2.0 allows a local user with write access to a lock marker file (but not removal rights) to forge the process ID in the marker. This causes another process running as the lock owner or root to incorrectly consider the lock stale, remove the live marker, and acquire the lock simultaneously. This results in two processes entering the critical section concurrently without error. The issue arises when the marker file is created with group or other write permissions, typically due to an explicit permissive mode or a lax umask in a sticky or non-removable directory.
References
- github.com/tox-dev/filelock/security/advisories/GHSA-rfpc-qcw5-3pc4 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-112939 (opens in a new tab)
- github.com/tox-dev/filelock/pull/836 (opens in a new tab)
- github.com/tox-dev/filelock/commit/eeceaa846cbe4df72718d94c8371ca1ab8f5b3cc (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)