Cloudanix VulnDB

CVE-2026-28434

Medium · 5.3

CVSS

5.3

EPSS

0.4%

Published

Mar 4, 2026

CISA due date

—

The record

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 packages

Ecosystem Package Introduced Fixed
openSUSE:Tumbleweed cpp-httplib 0 0.38.0-1.1

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