Yhirose: >> Cpp-Httplib Security Vulnerabilities
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.27.0, a vulnerability allows attacker-controlled HTTP headers to influence server-visible metadata, logging, and authorization decisions. An attacker can supply X-Forwarded-For or X-Real-IP headers which get accepted unconditionally by get_client_ip() in docker/main.cc, causing access and error logs (nginx_access_logger / nginx_error_logger) to record spoofed client IPs (log poisoning / audit evasion). This vulnerability is fixed in 0.27.0.
CVSS Score
5.3
EPSS Score
0.0
Published
2025-12-05
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.27.0, a vulnerability allows attacker-controlled HTTP headers to influence server-visible metadata, logging, and authorization decisions. An attacker can inject headers named REMOTE_ADDR, REMOTE_PORT, LOCAL_ADDR, LOCAL_PORT that are parsed into the request header multimap via read_headers() in httplib.h (headers.emplace), then the server later appends its own internal metadata using the same header names in Server::process_request without erasing duplicates. Because Request::get_header_value returns the first entry for a header key (id == 0) and the client-supplied headers are parsed before server-inserted headers, downstream code that uses these header names may inadvertently use attacker-controlled values. Affected files/locations: cpp-httplib/httplib.h (read_headers, Server::process_request, Request::get_header_value, get_header_value_u64) and cpp-httplib/docker/main.cc (get_client_ip, nginx_access_logger, nginx_error_logger). Attack surface: attacker-controlled HTTP headers in incoming requests flow into the Request.headers multimap and into logging code that reads forwarded headers, enabling IP spoofing, log poisoning, and authorization bypass via header shadowing. This vulnerability is fixed in 0.27.0.
CVSS Score
10.0
EPSS Score
0.0
Published
2025-12-05
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.20.1, cpp-httplib does not have a limit for a unique line, permitting an attacker to explore this to allocate memory arbitrarily. This vulnerability is fixed in 0.20.1. NOTE: This vulnerability is related to CVE-2025-53629.
CVSS Score
8.8
EPSS Score
0.0
Published
2025-07-10
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.23.0, incoming requests using Transfer-Encoding: chunked in the header can allocate memory arbitrarily in the server, potentially leading to its exhaustion. This vulnerability is fixed in 0.23.0. NOTE: This vulnerability is related to CVE-2025-53628.
CVSS Score
7.5
EPSS Score
0.001
Published
2025-07-10
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. In version 0.21.0, when many http headers fields are passed in, the library does not limit the number of headers, and the memory associated with the headers will not be released when the connection is disconnected. This leads to potential exhaustion of system memory and results in a server crash or unresponsiveness. Version 0.22.0 contains a patch for the issue.
CVSS Score
7.5
EPSS Score
0.001
Published
2025-06-26
cpp-httplib version v0.17.3 through v0.18.3 fails to filter CRLF characters ("\r\n") when those are prefixed with a null byte. This enables attackers to exploit CRLF injection that could further lead to HTTP Response Splitting, XSS, and more.
CVSS Score
5.3
EPSS Score
0.002
Published
2025-02-04
cpp-httplib through 0.5.8 does not filter \r\n in parameters passed into the set_redirect and set_header functions, which creates possibilities for CRLF injection and HTTP response splitting in some specific contexts.
CVSS Score
7.5
EPSS Score
0.002
Published
2020-04-12