Cpp Httplib

cpp-httplib is a C++ header-only HTTP/HTTPS library. From 0.29.0 until 0.51.0, Client::open_stream in httplib.h accepts a caller-controlled path that reaches detail::write_request_line() without the detail::encode_path() protection used by the ordinary buffered request path. Raw carriage-return and line-feed bytes in the path can therefore split the outbound HTTP/1.1 request line and inject attacker-shaped request metadata. Exploitation requires an embedding application to pass remote user input into the open_stream path and a backend or intermediary that interprets the injected bytes; the established impact is modification of backend-visible request data, not direct confidentiality or availability impact. This issue is fixed in version 0.51.0.

Published: 2026-10-14T18:19:38.256Z
Updated: 2026-10-15T15:06:40.241Z

cpp-httplib is a C++ header-only HTTP/HTTPS library. Prior to 0.51.0, create_redirect_client() removes Host, Proxy-Authorization, and Authorization headers when following a cross-origin 301, 302, 307, or 308 redirect but leaves Cookie headers attached. detail::redirect() copies the request for those redirect codes, so cookies supplied directly or through default_headers_ are sent to the redirect target. An attacker who controls a redirect response, or a network position for a non-HTTPS origin, can receive session cookies intended for the original origin. A 303 redirect is not affected because that path clears all request headers. This issue is fixed in version 0.51.0.

Published: 2026-10-14T18:18:21.598Z
Updated: 2026-10-15T14:48:03.087Z

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. In affected Mbed TLS backend versions from 0.31.0 through 0.46.1 and wolfSSL backend versions from 0.33.0 through 0.46.1, when cpp-httplib is built with CPPHTTPLIB_MBEDTLS_SUPPORT or CPPHTTPLIB_WOLFSSL_SUPPORT and a client connects to an IP-literal host with server certificate verification enabled, SSLClient and Client in HTTPS mode skip certificate chain validation and WebSocketClient on the Mbed TLS backend skips verification altogether, allowing a man-in-the-middle attacker positioned to intercept traffic to present a crafted certificate and read or modify the traffic. This issue is fixed in version 0.47.0.

Published: 2026-07-10T16:06:12.848Z
Updated: 2026-07-14T03:55:43.419Z

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.44.0, When the server has called Server::set_trusted_proxies() with a non-empty trusted-proxy list, an attacker can send an HTTP request that includes an X-Forwarded-For header whose value parses to no valid IP segments. The code path then executes get_client_ip(), which calls front() on an empty std::vector—undefined behavior in C++. On typical implementations this manifests as abnormal process termination (denial of service). With Sanitizers enabled, you get an explicit runtime diagnostic. This vulnerability is fixed in 0.44.0.

Published: 2026-05-29T19:18:26.615Z
Updated: 2026-06-01T13:52:30.508Z

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.

Published: 2026-05-29T19:21:12.313Z
Updated: 2026-06-01T17:57:44.116Z