shodan · filelock: SoftFileLock stale-break restore follows a swapped-in symbolic link and hard-links a file of the user
Affects shodanSource GCVE Database
Not known to be exploited · CVSS 5.3 Medium : upgrade to 1.31.0_12 when convenient.
Data as of 30 Oct 2026, 05:17 UTC
- Patch
- Available – fixed in 1.31.0_12
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 29 Oct 2026.
What to do
Upgrade shodan to 1.31.0_12.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewshodanpkg:brew/shodanOther 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 4.2.1 (fixed in 1.31.0_12 for the referenced product). Users should upgrade to this fixed version to remediate the vulnerability. Additionally, ensuring that shared lock directories have the sticky bit set (mode 1777) or are not writable by untrusted users will prevent exploitation. Linux kernel settings such as fs.protected_symlinks=1 also help mitigate the issue by preventing following of symbolic links in world-writable sticky directories. No other actions are required once patched or these conditions are met.
Description
A vulnerability in filelock versions 4.1.0 through 4.2.0 allows a local unprivileged user who can write to a shared lock directory without the sticky bit to exploit the soft-lock stale break restore mechanism. This flaw enables the attacker to cause the lock process to create a hard link to one of the lock user's own files, exposing file metadata and allowing the attacker to rename the link. On version 4.2.0, this can lead to truncation of the targeted file by the lock user. The issue arises due to symbolic link following behavior in os.link on CPython 3.12+ on Linux and macOS. The vulnerability requires specific conditions including a writable non-sticky directory shared by users on the same filesystem. The CVSS 3.1 score is 5.3 (Medium).
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)