{"id":"CVE-2026-28434","summary":"cpp-httplib's default exception handler leaks e.what() to clients via EXCEPTION_WHAT response header","details":"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.","aliases":["GHSA-8mpw-r4gc-xm7q"],"modified":"2026-04-02T13:26:34.783522Z","published":"2026-03-04T19:34:30.486Z","related":["openSUSE-SU-2026:10435-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28434.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-200"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28434.json"},{"type":"ADVISORY","url":"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-8mpw-r4gc-xm7q"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-28434"},{"type":"FIX","url":"https://github.com/yhirose/cpp-httplib/commit/defd907c7469c5c8281247b73bbd07be24c31164"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/yhirose/cpp-httplib","events":[{"introduced":"0"},{"fixed":"85b18a9c6431877188a706ba3c61679fa9de3e27"}]}],"versions":["latest","v0.10.0","v0.10.1","v0.10.2","v0.10.3","v0.10.4","v0.10.5","v0.10.6","v0.10.7","v0.10.8","v0.10.9","v0.11.0","v0.11.1","v0.11.2","v0.11.3","v0.11.4","v0.12.0","v0.12.1","v0.12.2","v0.12.3","v0.12.4","v0.12.5","v0.12.6","v0.13.0","v0.13.1","v0.13.2","v0.13.3","v0.14.0","v0.14.1","v0.14.2","v0.14.3","v0.15.0","v0.15.1","v0.15.2","v0.15.3","v0.16.0","v0.16.1","v0.16.2","v0.16.3","v0.17.0","v0.17.1","v0.17.2","v0.17.3","v0.18.0","v0.18.1","v0.18.2","v0.18.3","v0.18.4","v0.18.5","v0.18.6","v0.18.7","v0.19.0","v0.2.0","v0.2.1","v0.2.2","v0.2.3","v0.2.4","v0.2.5","v0.2.6","v0.20.0","v0.20.1","v0.21.0","v0.22.0","v0.23.0","v0.23.1","v0.24.0","v0.25.0","v0.26.0","v0.27.0","v0.28.0","v0.29.0","v0.3.0","v0.3.1","v0.3.2","v0.3.3","v0.30.0","v0.30.1","v0.30.2","v0.31.0","v0.32.0","v0.33.0","v0.33.1","v0.34.0","v0.4.0","v0.4.1","v0.4.2","v0.5.0","v0.5.1","v0.5.10","v0.5.11","v0.5.12","v0.5.13","v0.5.2","v0.5.3","v0.5.4","v0.5.5","v0.5.6","v0.5.7","v0.5.8","v0.5.9","v0.6.0","v0.6.1","v0.6.2","v0.6.3","v0.6.4","v0.6.5","v0.6.6","v0.6.7","v0.7.0","v0.7.1","v0.7.10","v0.7.11","v0.7.12","v0.7.13","v0.7.14","v0.7.15","v0.7.16","v0.7.17","v0.7.18","v0.7.2","v0.7.3","v0.7.4","v0.7.5","v0.7.6","v0.7.7","v0.7.8","v0.7.9","v0.8.0","v0.8.1","v0.8.2","v0.8.3","v0.8.4","v0.8.5","v0.8.6","v0.8.7","v0.8.8","v0.8.9","v0.9.0","v0.9.1","v0.9.10","v0.9.2","v0.9.3","v0.9.4","v0.9.5","v0.9.6","v0.9.7","v0.9.8","v0.9.9"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-28434.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"}]}