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 products
yhirose: cpp-httplib
References2
- github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64… ExploitMitigationVendor Advisory
- github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64… ExploitMitigationVendor Advisory
Metrics
- CVSS 3.1
-
9.9
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L - EPSS — exploit probability
- 0% percentile: 22 · as of 15 November 2026
- CWE
- CWE-93CWE-444
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