{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "erlang-cowlib"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.20.0-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "Improper Encoding or Escaping of Output vulnerability in ninenines cowlib allows Link header directive smuggling via unescaped special characters in cow_link:link/1.  cow_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 \u003e 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.  This issue affects cowlib: from 2.9.0 before 2.20.0.",
  "id": "DEBIAN-CVE-2026-43971",
  "modified": "2026-09-18T03:47:28.430541110Z",
  "published": "2026-08-18T09:17:14.340Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-43971"
    }
  ],
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ],
  "upstream": [
    "CVE-2026-43971"
  ]
}