Race Condition Vulnerability in Perl Affects File Operations
CVE-2025-40909

5.9MEDIUM

Key Information:

Vendor

Perl

Status
Perl
Vendor
CVE Published:
30 May 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2025-40909?

A race condition in Perl's thread handling may allow file operations to target unintended paths, potentially leading to the execution of malicious code or unauthorized access to sensitive files. This issue occurs when a directory handle is open during thread creation, temporarily modifying the current working directory for new threads and making it visible to other threads. Attackers can exploit this flaw to manipulate file access in unexpected ways, thus compromising system integrity.

Affected Version(s)

perl 5.13.6 < 5.41.13

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2025-40909 - Proof of Concept

References

https://github.com/Perl/perl5/commit/918bfff86ca8d6d4e4ec...
patch
https://www.openwall.com/lists/oss-security/2025/05/22/2
mailing-listexploit
https://github.com/Perl/perl5/issues/23010
issue-tracking

CVSS V3.1

Score:
5.9
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Vincent Lefevre
.
CVE-2025-40909 : Race Condition Vulnerability in Perl Affects File Operations