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CVE-2026-112908VulnerabilityPublished

poetry · filelock: StrictSoftFileLock creates its claim directories without the lock mode, so another local user with a write

Affects poetrySource GCVE Database

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Not known to be exploited · CVSS 5.3 Medium : upgrade to 2.5.1_1 when convenient.

Data as of 30 Oct 2026, 08:30 UTC

CVSS 3.1 base score
5.3Medium
How severe the flaw is on the 0–10 CVSS scale.
Patch
Available – fixed in 2.5.1_1
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 29 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
Homebrewpoetrypkg:brew/poetryOther threatsAffected
  • >=2.4.2 <2.5.1_1
Fixed in
  • 2.5.1_1

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

A fix is available in poetry version 2.5.1_1. Users should upgrade to this version to resolve the vulnerability. Additionally, existing <path>.filelock directories created by affected versions may retain insecure permissions; these should be removed or have their permissions corrected (e.g., via chmod) during upgrade. Avoid using lax umask settings (such as 000 or 002 with group write) or permissive default ACLs on the lock's parent directories to reduce risk.

Description

The filelock vulnerability (CVE-2026-112908) affects versions of the poetry package >=2.4.2 and <2.5.1_1. It involves the StrictSoftFileLock and AsyncStrictSoftFileLock classes creating claim directories without applying the intended restrictive mode, resulting in directories that may be writable by other local users under certain umask or ACL configurations. This allows another local user with write access to unlink claim files, causing the lock to be bypassed and potentially allowing concurrent holders to write protected data without detection. The vulnerability has a medium severity with a CVSS score of 5.3 and is fixed in version 2.5.1_1.

References

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