CVE-2026-28434
Description
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.35.0, when a request handler throws a C++ exception and the application has not registered a custom exception handler via set_exception_handler(), the library catches the exception and writes its message directly into the HTTP response as a header named EXCEPTION_WHAT. This header is sent to whoever made the request, with no authentication check and no special configuration required to trigger it. The behavior is on by default. A developer who does not know to opt in to set_exception_handler() will ship a server that leaks internal exception messages to any client. This vulnerability is fixed in 0.35.0.
How to fix
- yhirose cpp-httplib0.35.0 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| yhirose cpp-httplib | v < 0.35.0 | 0.35.0 |
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