{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "cpe": "cpe:2.3:a:ninenines:gun:*:*:*:*:*:*:*:*",
            "extracted_events": [
              {
                "introduced": "2.0.0"
              },
              {
                "fixed": "2.4.0"
              }
            ],
            "source": [
              "CPE_RANGE",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "33223e751267c5f249f3db1277c13904a1801b92"
            },
            {
              "fixed": "8cc70ed78fc946e5d9c49e92d84bde64ca12db1f"
            },
            {
              "fixed": "567863ff53802fed21c3b3f25812db7f7ae29676"
            }
          ],
          "repo": "https://github.com/ninenines/gun",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-346"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43972.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "871989eef53663285c165fdfb83a5918ebe00d41"
          },
          {
            "fixed": "567863ff53802fed21c3b3f25812db7f7ae29676"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Origin Validation Error vulnerability in ninenines gun (gun_http2 module) allows cross-origin cookie injection via unvalidated HTTP/2 PUSH_PROMISE authority.\n\nIn gun_http2:push_promise_frame/7, the :authority pseudo-header from an incoming PUSH_PROMISE frame is stored verbatim into the promised stream record without checking that it matches the connection's origin. When gun_http2:headers_frame/9 later processes the response headers for the promised stream, it calls gun_cookies:set_cookie_header/7 with the unvalidated server-supplied authority before any status branching and before user code can act. This violates RFC 7540 §10.6 / RFC 9113 §8.4, which require receivers to treat as a protocol error any push for a resource the server is not authoritative for.\n\nA malicious or compromised HTTP/2 server can plant cookies scoped to arbitrary third-party domains into the client's shared cookie store. This enables session fixation attacks against those domains and, if the planted cookie overrides a legitimate session token, may result in account takeover. No user interaction beyond making a normal HTTP/2 request to the attacker-controlled server is required.\n\nThis issue affects gun: from 2.0.0 before 2.4.0.",
  "id": "CVE-2026-43972",
  "modified": "2026-08-20T03:30:43.433118437Z",
  "published": "2026-06-08T14:12:38.780Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-43972"
    },
    {
      "type": "ADVISORY",
      "url": "https://cna.erlef.org/cves/CVE-2026-43972.html"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43972.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-43972"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ninenines/gun/commit/567863ff53802fed21c3b3f25812db7f7ae29676"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/ninenines/gun"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/ninenines/gun.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "gun HTTP/2 PUSH_PROMISE authority not validated against connection origin allows cross-origin cookie injection"
}