← CVE Intelligence

CVE-2026-28434

cpp-httplib's default exception handler leaks e.what() to clients via EXCEPTION_WHAT response header PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / productVersions
yhirose / cpp-httplibaffected < 0.35.0

CWE

CWE-200

References

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.