cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection_CVE-2026-45372

{
    "lastseen": "",
    "description": "cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.44.0, when cpp-httplib's server parses an incoming request, it applies percent-decoding to every header value except Location and Referer. The validity check (is_field_value) is run before decoding, so encoded %0D%0A passes the check and is then expanded to a literal \\r\\n byte pair inside the stored header value. This vulnerability is fixed in 0.44.0.",
    "published": "2026-05-29T19:21:12.313Z",
    "modified": "2026-05-29T19:21:12.313Z",
    "type": "cve",
    "title": "cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection",
    "source": "GitHub_M",
    "references": "https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-xjxg-64p4-vj4m",
    "id": "CVE-2026-45372",
    "bulletinFamily": "",
    "cwe": [
        "CWE-93",
        "CWE-444"
    ],
    "cvelist": null,
    "sourceData": "yhirose cpp-httplib < 0.44.0",
    "sourceHref": "",
    "cvss": {
        "score": 9.9,
        "severity": "CRITICAL",
        "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L",
        "version": "3.1"
    },
    "cvss2": [],
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        "confidentialityImpact": "",
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        "availabilityImpact": "",
        "cvssV3": {
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    "href": "",
    "category_name": "CVE",
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    "product": "cpp-httplib",
    "version": "< 0.44.0",
    "vendor": "yhirose",
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}