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.
CVSS Metrics
- Vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- Attack Vector
- network
- Complexity
- low
- Privileges
- none
- User Action
- none
- Scope
- unchanged
- Confidentiality
- low
- Integrity
- none
- Availability
- none
- Weaknesses
- CWE-200NVD-CWE-noinfo
Metadata
- Primary Vendor
- YHIROSE
- Published
- 3/4/2026
- Last Modified
- 3/5/2026
- Source
- NIST NVD
- Note: Verify all details with official vendor sources before applying patches.
Affected Products
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