Vulnerability in Perl
CVE-2025-40909
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
EPSS: 0.004 (29.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
Affected products
- Perl — versions 5.13.6
Weakness classification (CWE)
Public proof-of-concept exploits
References
- 9b29abf9-4ab0-4765-b253-1875cd9b441e (patch)
- 9b29abf9-4ab0-4765-b253-1875cd9b441e (mailing-list, exploit)
- 9b29abf9-4ab0-4765-b253-1875cd9b441e (issue-tracking)
- 9b29abf9-4ab0-4765-b253-1875cd9b441e (related)
- 9b29abf9-4ab0-4765-b253-1875cd9b441e (related)
- 9b29abf9-4ab0-4765-b253-1875cd9b441e (related)
- 9b29abf9-4ab0-4765-b253-1875cd9b441e (related)
- af854a3a-2127-422b-91ae-364da2661108
- af854a3a-2127-422b-91ae-364da2661108
- af854a3a-2127-422b-91ae-364da2661108
Frequently asked questions
- What is CVE-2025-40909?
- CVE-2025-40909 is a medium-severity vulnerability in Perl, classified under Untrusted Search Path. CVSS score: 5.9/10. Published 2025-05-30.
- How severe is CVE-2025-40909?
- Medium severity. CVSS v3 base score is 5.9 out of 10.
- Is CVE-2025-40909 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.