CVE-2025-40907

FCGI versions 0.44 through 0.82, for Perl, include a vulnerable version of the FastCGI fcgi2 (aka fcgi) library

MEDIUM
5.3
CVSS Score
Published: May 16, 2025 at 01:03 PM UTC
Updated: June 17, 2026 at 09:22 AM UTC
2 products affected across 2 vendorsFcgiFCGI

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Severity
MEDIUM5.3
Exploit prediction
EPSS 0.7%
SSVC
PoC

Description

FCGI versions 0.44 through 0.82, for Perl, include a vulnerable version of the FastCGI fcgi2 (aka fcgi) library. The included FastCGI library is affected by CVE-2025-23016, causing an integer overflow (and resultant heap-based buffer overflow) via crafted nameLen or valueLen values in data to the IPC socket. This occurs in ReadParams in fcgiapp.c.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

0.44 ≤ v ≤ 0.82
0.44 ≤ v ≤ 0.820.44

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (6)

Mailing ListThird Party Advisory
Source: 9b29abf9-4ab0-4765-b253-1875cd9b441e
http://www.openwall.com/lists/oss-security/2025/04/23/4
Issue TrackingExploit
Source: 9b29abf9-4ab0-4765-b253-1875cd9b441e
https://github.com/FastCGI-Archives/fcgi2/issues/67
PatchRelease Notes
Source: 9b29abf9-4ab0-4765-b253-1875cd9b441e
https://github.com/FastCGI-Archives/fcgi2/releases/tag/2.4.5
Issue TrackingExploit
Source: 9b29abf9-4ab0-4765-b253-1875cd9b441e
https://github.com/perl-catalyst/FCGI/issues/14
Technical DescriptionExploitThird Party Advisory
Source: 9b29abf9-4ab0-4765-b253-1875cd9b441e
https://www.synacktiv.com/en/publications/cve-2025-23016-exploiting-the-fastcgi-library

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMCISA-ADP
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusANALYZED
CWE
CWE-122CWE-190CWE-1395

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