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.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Ubuntu | — | Upgrade libcpp-httplib0.14t64 (Ubuntu Pro)Upgrade libcpp-httplib0.18Upgrade libcpp-httplib-dev (Ubuntu Pro)Upgrade libcpp-httplib0 (Ubuntu Pro)Upgrade libcpp-httplib0.26 (Ubuntu Pro)Upgrade libcpp-httplib-dev | Jun 25, 2026 | May 29, 2026 |
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