Vulnerability 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 Score
MEDIUM
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Yhirose | Cpp-Httplib | < 0.35.0 |
Related Weaknesses (CWE)
References
- https://github.com/yhirose/cpp-httplib/commit/defd907c7469c5c8281247b73bbd07be24Patch
- https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-8mpw-r4gc-xm7qExploitMitigationVendor Advisory
FAQ
What is CVE-2026-28434?
CVE-2026-28434 is a vulnerability with a CVSS score of 5.3 (MEDIUM). 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 excepti...
How severe is CVE-2026-28434?
CVE-2026-28434 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-28434?
Check the references section above for vendor advisories and patch information. Affected products include: Yhirose Cpp-Httplib.