{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0.1.0"
              },
              {
                "fixed": "0.16.2"
              }
            ],
            "source": [
              "DESCRIPTION",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "8e43e7285931741e2b9aecf90c8439bb84ca8e4c"
            },
            {
              "fixed": "3b7e43abf60fa30c40985e4043965ec67791b4dc"
            },
            {
              "fixed": "2d4d1d94aae7790ae0623063961adbeef171fa71"
            },
            {
              "fixed": "2fd91a5ecbd0b0ad2a4ac202b79659e8126dbc0b"
            }
          ],
          "repo": "https://github.com/zenhive/mpp",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-82qh-vrvm-gqvc"
  ],
  "database_specific": {
    "cna_assigner": "EEF",
    "cwe_ids": [
      "CWE-524"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89186.json",
    "unresolved_ranges": [
      {
        "extracted_events": [
          {
            "introduced": "2d4d1d94aae7790ae0623063961adbeef171fa71"
          },
          {
            "fixed": "2fd91a5ecbd0b0ad2a4ac202b79659e8126dbc0b"
          }
        ],
        "source": "AFFECTED_FIELD"
      }
    ]
  },
  "details": "Use of Cache Containing Sensitive Information in ZenHive mpp allows a shared HTTP cache to store a paid response and serve it to clients that never paid.\n\nMPP.Plug.verify_credential in lib/mpp/plug.ex sets payment-receipt and cache-control: private on the connection before the wrapped application runs, and registers no register_before_send/2 callback. Plug.Conn.put_resp_header/3 replaces an existing header, so a mounting application that sets its own cache-control on the paid resource (for example public, max-age=3600) silently overrides the private the library relies on, and a CDN or reverse proxy can then store the paid 200 together with its Payment-Receipt and serve both to unpaid clients. The library-level guarantee is therefore defeatable by the application it protects. For the same reason a downstream non-2xx response still carried Payment-Receipt, issuing a receipt for a response that delivered no resource.\n\nThis issue affects mpp: from 0.1.0 before 0.16.2.",
  "id": "CVE-2026-89186",
  "modified": "2026-09-18T03:30:31.298722569Z",
  "published": "2026-09-16T08:24:15.058Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cna.erlef.org/cves/CVE-2026-89186.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com"
    },
    {
      "type": "WEB",
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-89186"
    },
    {
      "type": "WEB",
      "url": "https://repo.hex.pm"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89186.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/ZenHive/mpp/security/advisories/GHSA-82qh-vrvm-gqvc"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89186"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ZenHive/mpp/commit/2d4d1d94aae7790ae0623063961adbeef171fa71"
    },
    {
      "type": "FIX",
      "url": "https://github.com/ZenHive/mpp/commit/2fd91a5ecbd0b0ad2a4ac202b79659e8126dbc0b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/ZenHive/mpp"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "mpp writes Payment-Receipt and Cache-Control before the wrapped application runs, letting a consumer's own Cache-Control expose paid responses to shared caches"
}