CVE-2025-40909

What it is

Perl threads have a working directory race condition where file operations may target unintended paths. If a directory handle is open at thread creation, the process-wide current working directory is temporarily changed in order to clone that handle for the new thread, which is visible from any third (or more) thread already running. This may lead to unintended operations such as loading code or accessing files from unexpected locations, which a local attacker may be able to exploit. The bug was introduced in commit 11a11ecf4bea72b17d250cfb43c897be1341861e and released in Perl version 5.13.6

At a glance

Exploitability

Can be exploited locally on the machine without logging in. Limited direct impact.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2025-05-30 13:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 09:22 UTC Last updatedMost recent change to the record

Details

Published

2025-05-30 13:15 UTC

Last modified

2026-06-17 09:22 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-426

Record status

Deferred

Attack profile CVSS 3.1 · 5.9

Attack vector

Local

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

Low

Integrity

Low

Availability

Low