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CVE-2025-23016VulnerabilityPublished Updated

FastCGI fcgi2 (aka fcgi) 2.x through 2.4.4 has an integer overflow (and resultant heap-based buffer overflow) via

Source GCVE Database

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Not known to be exploited · CVSS 9.3 Critical.

Data as of 29 Oct 2026, 23:52 UTC

CVSS 3.1 base score
9.3Critical
How severe the flaw is on the 0–10 CVSS scale.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 10 Jan 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

AI-suggested

Until a fix is available, restrict access to the IPC socket to trusted users only and monitor for suspicious activity related to FastCGI processes.

Description

FastCGI fcgi2 versions 2.x through 2.4.4 contain an integer overflow vulnerability in the ReadParams function of fcgiapp.c. This overflow can lead to a heap-based buffer overflow when processing crafted nameLen or valueLen values sent to the IPC socket. The vulnerability has a high severity with a CVSS score of 9.3, indicating critical impact on confidentiality, integrity, and availability.

References

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