poetry · filelock: SoftReadWriteLock holder refresh writes through a hard link and hangs on a named pipe that another local
Affects poetrySource GCVE Database
Not known to be exploited · CVSS 6.1 Medium : upgrade to 2.5.1_1 when convenient.
Data as of 30 Oct 2026, 08:30 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 6.1 |
|---|
- Patch
- Available – fixed in 2.5.1_1
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:L/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 29 Oct 2026.
What to do
Upgrade poetry to 2.5.1_1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewpoetrypkg:brew/poetryOther 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 fixed the issue in poetry version 2.5.1_1. Users should upgrade to this version or later to remediate the vulnerability. No additional mitigation is required if the patch is applied. The vulnerability depends on the attacker owning the lock's .rw directory and on kernel settings permitting hard links to files not owned by the user; restricting directory permissions and enabling fs.protected_hardlinks=1 on Linux can reduce risk but do not replace patching.
Description
A vulnerability in filelock versions 4.0.0 through 4.2.0 allows a local user who owns the lock's .rw directory tree to interfere with the lock holder's refresh operations. By replacing the holder record with a FIFO (named pipe), the attacker can cause the lock holder's write or read lock operations to hang indefinitely, preventing heartbeat refreshes and allowing multiple processes to believe they hold the lock simultaneously. Additionally, on systems where the kernel permits hard links to files not owned by the user (e.g., Linux with fs.protected_hardlinks=0), the attacker can cause the lock holder to overwrite the first ~135 bytes of one of its own private files with lock holder data. The vulnerability has a CVSS score of 6.1 (Medium) and affects local users with low privileges but no confidentiality impact.
References
- github.com/tox-dev/filelock/security/advisories/GHSA-fj95-fr6c-h845 (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-112934 (opens in a new tab)
- github.com/tox-dev/filelock/pull/842 (opens in a new tab)
- github.com/tox-dev/filelock/commit/bfa066d65a1ba9106f86ee9d027f7588b9c77e03 (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)