What is CVE-2025-23016?

CVE-2025-23016 is a critical-severity vulnerability in Fastcgi Fcgi, classified under Integer Overflow or Wraparound. CVSS score: 9.3/10. Published 2025-01-10.

How severe is CVE-2025-23016?

Critical severity. CVSS v3 base score is 9.3 out of 10.

Is CVE-2025-23016 known to be exploited?

8 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Integer overflow in Fastcgi Fcgi

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.

Vulnerability class: Integer Overflow

EPSS: 0.006 (42.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.3 (Critical). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Affected products

Fastcgi Fcgi — versions 2.0.0

Weakness classification (CWE)

CWE-190 — Integer Overflow or Wraparound

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-23016?: CVE-2025-23016 is a critical-severity vulnerability in Fastcgi Fcgi, classified under Integer Overflow or Wraparound. CVSS score: 9.3/10. Published 2025-01-10.
How severe is CVE-2025-23016?: Critical severity. CVSS v3 base score is 9.3 out of 10.
Is CVE-2025-23016 known to be exploited?: 8 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.