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CVSS v3.1
9.9
EPSS
0.29%
Published
May 29, 2026
Modified
May 29, 2026
Public PoC / Exploit
All weaponized →No public PoC or exploit code indexed for this CVE.
Links to public security research (Exploit-DB, Nuclei, Trickest, GitHub) for defensive use only.
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.
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:LWeaknesses (CWE)