Buffer overflow in Ether Fcgi

CVE-2025-40907

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 ove…

Vulnerability class: Buffer Overflow

EPSS: 0.005 (39.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-40907?
CVE-2025-40907 is a medium-severity vulnerability in Ether Fcgi, classified under Heap-based Buffer Overflow. CVSS score: 5.3/10. Published 2025-05-16.
How severe is CVE-2025-40907?
Medium severity. CVSS v3 base score is 5.3 out of 10.
Is CVE-2025-40907 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.