CVE-2026-28434

MEDIUM

5.3

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.

CVE Details

CVSS v3.1 Score5.3

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published3/4/2026

Last Modified3/5/2026

Sourcenvd

Honeypot Sightings0

Affected Products

yhirose:cpp-httplib

Weaknesses (CWE)

CWE-200

References

https://github.com/yhirose/cpp-httplib/commit/defd907c7469c5c8281247b73bbd07be24c31164(security-advisories@github.com)

https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-8mpw-r4gc-xm7q(security-advisories@github.com)

IOC Correlations

No correlations recorded

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