CVE-2026-45372
CRITICAL9.9EPSS 0.04%Published: 5/29/2026Modified: 5/30/2026
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.
Affected packages (1)
- Debian/cpp-httplibfrom 0
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | CRITICAL9.9 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L |