CVE-2026-45372

critical

Description

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 validity check (is_field_value) is run before decoding, so encoded %0D%0A passes the check and is then expanded to a literal \r\n byte pair inside the stored header value. This vulnerability is fixed in 0.44.0.

References

https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m

Details

Source: Mitre, NVD

Published: 2026-05-29

Updated: 2026-05-29

Risk Information

CVSS v2

Base Score: 9

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:C/A:P

Severity: High

CVSS v3

Base Score: 9.9

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

Severity: Critical

EPSS

EPSS: 0.00041