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Vulnerabilities

Vulnerability · CVE-2025-40909

ALAS-2025-1981 (medium): perl

Published May 30, 2025 · catalog updated Apr 18, 2026 · ALAS-2025-1981 (medium): perl

Check if you run it

No confirmed exploitation is on record for CVE-2025-40909. EPSS is 0.50%. Act only if a listed version of ALAS-2025-1981 (medium): perl is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (ALAS-2025-1981 (medium): perl).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.9
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.50%
Remediation
Version ranges on file
Affected products
vendor perl perl 5.13.6 <5.41.13

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

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor perl perl 5.13.6 <5.41.135.13.6 <5.41.13

How to fix CVE-2025-40909

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2025-40909. EPSS is 0.50%. Act only if a listed version of ALAS-2025-1981 (medium): perl is installed.

Which versions are affected?

Compare what you have installed with perl perl 5.13.6 <5.41.13 5.13.6 <5.41.13. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.50%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 9, 2025 · Amazon Linux

    Detected

    CVE-2025-40909

  2. Apr 18, 2026 · EUVD

    Updated

    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 a

Sources

  • Amazon LinuxVendor advisoryCVE-2025-40909

    CVE-2025-40909

    alas.aws.amazon.com
  • CVE.orgVulnerability recordCVE-2025-40909

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-40909

    30-day exploitation probability 0.5%

    first.org
  • EUVDVulnerability recordEUVD-2025-16506

    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 v

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.