CVE-2025-46728 Information

Description

cpp-httplib is a C++ header-only HTTP/HTTPS server and client library. Prior to version 0.20.1 the library fails to enforce configured size limits on incoming request bodies when Transfer-Encoding: chunked is used or when no Content-Length header is provided. A remote attacker can send a chunked request without the terminating zero-length chunk causing uncontrolled memory allocation on the server. This leads to potential exhaustion of system memory and results in a server crash or unresponsiveness. Version 0.20.1 fixes the issue by enforcing limits during parsing. If the limit is exceeded at any point during reading the connection is terminated immediately. A short-term workaround through a Reverse Proxy is available. If updating the library immediately is not feasible deploy a reverse proxy (e.g. Nginx HAProxy) in front of the cpp-httplib application. Configure the proxy to enforce maximum request body size limits thereby stopping excessively large requests before they reach the vulnerable library code.

Reference

https://github.com/yhirose/cpp-httplib/commit/7b752106ac42bd5b907793950d9125a0972c8e8e https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-px83-72rx-v57c