{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "85b18a9c6431877188a706ba3c61679fa9de3e27"
            }
          ],
          "repo": "https://github.com/yhirose/cpp-httplib",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-8mpw-r4gc-xm7q"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-200"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/28xxx/CVE-2026-28434.json"
  },
  "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.",
  "id": "CVE-2026-28434",
  "modified": "2026-04-01T23:08:34.682782700Z",
  "published": "2026-03-04T19:34:30.486Z",
  "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"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "cpp-httplib's default exception handler leaks e.what() to clients via EXCEPTION_WHAT response header"
}