CVE-2025-23016

Description

FastCGI fcgi2 (aka fcgi) 2.x through 2.4.4 has 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.

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CVSS v3.1 Score

9.3

CRITICAL

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Weakness Type (CWE)

CWE-190 Integer Overflow

References

Other References

https://github.com/FastCGI-Archives/fcgi2/issues/67 https://github.com/FastCGI-Archives/fcgi2/releases/tag/2.4.5 https://www.synacktiv.com/en/publications/cve-2025-23016-exploiting-the-fastcgi-library http://www.openwall.com/lists/oss-security/2025/04/23/4 https://lists.debian.org/debian-lts-announce/2025/10/msg00009.html https://www.synacktiv.com/en/publications/cve-2025-23016-exploiting-the-fastcgi-library

Frequently Asked Questions

What is CVE-2025-23016? +

FastCGI fcgi2 (aka fcgi) 2.x through 2.4.4 has 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. It has a CVSS v3.1 base score of 9.3 (CRITICAL).

How severe is CVE-2025-23016? +

CVE-2025-23016 has a CVSS v3.1 score of 9.3 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately.

How do I check if I'm vulnerable to CVE-2025-23016? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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