{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "16.0.0"
              },
              {
                "fixed": "17.13.8"
              },
              {
                "introduced": "18.0.0"
              },
              {
                "fixed": "18.2.9"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "b0356892c9342d340eab73f11d4086c0ceeebb9a"
            },
            {
              "introduced": "55b0096347c8bd963a9fc04060985344bb69f9ad"
            },
            {
              "fixed": "4ae6af96f7990fdb336aa8ad7dee5e9f847d084a"
            },
            {
              "fixed": "fc3f3bcb58ce7c3d2e7645bc7b17f012a2e7649b"
            },
            {
              "fixed": "5b8333c9177e08b4ef4ed02903c2d657084e7afb"
            }
          ],
          "repo": "https://github.com/hapijs/joi",
          "type": "GIT"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "VulnCheck",
    "cwe_ids": [
      "CWE-1321"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90771.json"
  },
  "details": "joi before versions 17.13.8 and 18.2.9 contains a prototype pollution vulnerability in the messages compilation function that accepts __proto__ as an error code. Attackers can supply __proto__ keys in custom messages to replace the returned object's prototype, breaking downstream code relying on Object.prototype methods.",
  "id": "CVE-2026-90771",
  "modified": "2026-09-17T03:30:16.097557366Z",
  "published": "2026-09-13T10:45:42.498Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/90xxx/CVE-2026-90771.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-90771"
    },
    {
      "type": "ADVISORY",
      "url": "https://www.vulncheck.com/advisories/joi-before-17.13.8-and-18.2.9-prototype-pollution-via-messages"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/hapijs/joi/issues/3150"
    },
    {
      "type": "FIX",
      "url": "https://github.com/hapijs/joi/commit/5b8333c9177e08b4ef4ed02903c2d657084e7afb"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/hapijs/joi"
    },
    {
      "type": "ARTICLE",
      "url": "https://github.com/hapijs/joi/blob/v18.2.8/lib/messages.js"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "joi before 17.13.8 and 18.2.9 Prototype Pollution via messages"
}