{
  "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-2026-43971",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2026-43971",
    "idYear": 2026,
    "status": "PUBLISHED",
    "publishedAt": "2026-08-18T09:01:53.199Z",
    "updatedAt": "2026-09-16T20:24:09.279Z",
    "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": "Link Header Directive Smuggling via Unescaped target/rel/Attribute Keys in cow_link:link/1",
      "summary": "Improper Encoding or Escaping of Output vulnerability in ninenines cowlib allows Link header directive smuggling via unescaped special characters in cow_link:link/1.\n\ncow_link:do_link/1 in cowlib interpolates the target URI, rel value, and attribute keys directly into the serialized Link: header value without escaping or token-grammar validation. A > byte in target prematurely closes the URI slot, allowing an attacker to append additional link entries with attacker-chosen rel directives. A \" or \\ in rel escapes the quoted string and opens new parameters. Any byte — including whitespace, =, and \" — in an attribute key is emitted verbatim. Because browsers act on Link: directives such as rel=\"preconnect\", rel=\"preload\", and rel=\"prerender\", an attacker who can influence these fields in an application that round-trips parsed Link headers through cow_link:link/1 can force victim browsers to make out-of-band connections to attacker-controlled origins.\n\nThis issue affects cowlib: from 2.9.0 before 2.20.0.",
      "affected": [
        {
          "vendor": "ninenines",
          "product": "cowlib",
          "packageName": "cowlib",
          "collectionURL": "https://repo.hex.pm",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "2.9.0",
              "status": "affected",
              "versionType": "semver",
              "lessThan": "2.20.0"
            }
          ]
        },
        {
          "vendor": "ninenines",
          "product": "cowlib",
          "packageName": "ninenines/cowlib",
          "collectionURL": "https://github.com",
          "defaultStatus": "unaffected",
          "versions": [
            {
              "version": "485d58dfa91b91d98135dc95e5615f421715dae5",
              "status": "affected",
              "versionType": "git",
              "lessThan": "89da27ee4c241f5d649ba7d9b7f2188918af6cea"
            }
          ]
        }
      ]
    }
  }
}