{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2026-43966",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-43966",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-06-08T16:34:33.364Z",
    "updatedAt": "2026-10-14T09:22:13.888Z",
    "importedAt": "2026-10-24T01:58:14.884Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "HTTP Response Splitting via Non-VCHAR Bytes in cow_http_struct_hd:escape_string/2",
      "summary": "Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Request/Response Splitting') vulnerability in ninenines cowlib allows HTTP response splitting via non-VCHAR bytes in structured-fields string values.\n\ncow_http_struct_hd:escape_string/2 in cowlib only escapes \\ and \", passing all other bytes through verbatim. This creates an encoder/decoder asymmetry: the matching parser accepts only printable ASCII (0x20–0x7E, excluding \" and \\), but the encoder emits any byte including CR and LF. An application that builds a structured HTTP header via cow_http_struct_hd:item/1 (or a higher-level wrapper such as cow_http_hd:wt_protocol/1) from attacker-controlled input can have \\r\\n injected into the serialized header value. Once on the wire, the injected CRLF terminates the current header and any following bytes are interpreted as a new header, enabling HTTP response splitting.\n\nThis issue affects cowlib: from 2.9.0 onward.",
      "affected": [
        {
          "vendor": "ninenines",
          "product": "cowlib",
          "packageName": "cowlib",
          "collectionURL": "https://repo.hex.pm",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "2.9.0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "*"
            }
          ]
        },
        {
          "vendor": "ninenines",
          "product": "cowlib",
          "packageName": "ninenines/cowlib",
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "a8b793db3d6ffe91d62f81baf41b1dab4cd78fb6",
              "status": "affected",
              "versionType": "git",
              "lessThan": "4401b858f2229abb3ea115c60924f6c77e5f8aa3"
            }
          ]
        }
      ]
    }
  }
}