Medium
cpp-httplib — security advisory
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.
- Products
- cpp-httplib
- Affected versions
- 0.10.1+ds-1, 0.10.2+ds-1, 0.10.3+ds-1, 0.10.3+ds-1ubuntu0.1~esm1, 0.10.3+ds-1ubuntu0.1~esm2, 0.13.1+ds-1ubuntu1, 0.14.3+ds-1, 0.14.3+ds-1.1, 0.14.3+ds-1.1build1, 0.14.3+ds-1.1build2, 0.14.3+ds-1.1ubuntu0.1~esm1, 0.14.3+ds-1.1ubuntu0.1~esm2, 0.18.7-1, 0.18.7-1ubuntu0.25.10.1, 0.18.7-1ubuntu0.25.10.2, 0.26.0+ds-2ubuntu2, 0.26.0+ds-2ubuntu3, 0.26.0+ds-2ubuntu3+esm1, 0.26.0+ds-2ubuntu4, 0.9.10+ds-1, 0.9.9+ds-1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-28434
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:06 UTC · Revision 1
Source evidence
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.
osv:UBUNTU-CVE-2026-28434
cpp-httplib
Fixed versions: Not specified
cpp-httplib
Fixed versions: Not specified
cpp-httplib
Fixed versions: Not specified
cpp-httplib
Fixed versions: Not specified
cpp-httplib
Fixed versions: Not specified
Complete source record
{
"id": "803e713236937b184ee9e9da91285dcdf829ad80854703657614924645d6178f",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-28434",
"method": "structured",
"payload": {
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"title": "UBUNTU-CVE-2026-28434",
"summary": "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.",
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"modified": "2026-10-17T12:58:07.572782495Z",
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"references": [
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"https://www.cve.org/CVERecord?id=CVE-2026-28434",
"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-8mpw-r4gc-xm7q",
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"source_id": "core-osv",
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"published_at": "2026-03-04T20:16:00+00:00"
}