Integer Overflow Vulnerability in FastCGI Library for Perl
CVE-2025-40907

5.3MEDIUM

Key Information:

Vendor

Ether

Status
Fcgi
Vendor
CVE Published:
16 May 2025

Badges

👾 Exploit Exists🟡 Public PoC

What is CVE-2025-40907?

The FastCGI library versions 0.44 through 0.82 for Perl are vulnerable to an integer overflow that can result in a heap-based buffer overflow. This vulnerability is triggered by improperly handled nameLen or valueLen parameters in data sent to the IPC socket, specifically during the ReadParams function in the fcgiapp.c file. Exploiting this flaw may allow attackers to execute arbitrary code or crash affected services. It is crucial for organizations using these FastCGI versions to apply the necessary patches to safeguard their systems.

Affected Version(s)

FCGI 0.44 <= 0.82

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-2025-40907 - Proof of Concept

References

http://www.openwall.com/lists/oss-security/2025/04/23/4
mailing-list
https://github.com/FastCGI-Archives/fcgi2/issues/67
issue-tracking
https://github.com/FastCGI-Archives/fcgi2/releases/tag/2.4.5
patch

CVSS V3.1

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

Synacktiv
.
CVE-2025-40907 : Integer Overflow Vulnerability in FastCGI Library for Perl