What is CVE-2026-45372?

CVE-2026-45372 is a critical-severity vulnerability in Yhirose Cpp-httplib, classified under CRLF Injection. CVSS score: 9.9/10. Published 2026-05-29.

How severe is CVE-2026-45372?

Critical severity. CVSS v3 base score is 9.9 out of 10.

Vulnerability in Yhirose Cpp-httplib

CVE-2026-45372

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.44.0, when cpp-httplib's server parses an incoming request, it applies percent-decoding to every header value except Location and Referer. The val…

Vulnerability class: CRLF Injection

EPSS: 0.001 (17.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.9 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L.

Affected products

Yhirose Cpp-httplib — versions < 0.44.0

Weakness classification (CWE)

CWE-93 — CRLF Injection
CWE-444 — Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling)

References

security-advisories@github.com (x_refsource_CONFIRM, Exploit, Mitigation, Vendor Advisory)

Frequently asked questions

What is CVE-2026-45372?: CVE-2026-45372 is a critical-severity vulnerability in Yhirose Cpp-httplib, classified under CRLF Injection. CVSS score: 9.9/10. Published 2026-05-29.
How severe is CVE-2026-45372?: Critical severity. CVSS v3 base score is 9.9 out of 10.