{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "0"
              },
              {
                "fixed": "6.6.10"
              }
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "a55e6f21abf0f8c5a7d7d49b5c3b78498023fc7b"
            }
          ],
          "repo": "https://github.com/mikro-orm/mikro-orm",
          "type": "GIT"
        },
        {
          "database_specific": {
            "versions": [
              {
                "introduced": "7.0.0-rc.0"
              },
              {
                "fixed": "7.0.6"
              }
            ]
          },
          "events": [
            {
              "introduced": "a2330d20c18a6f1416bc4b90fd26acf3b5896fea"
            },
            {
              "fixed": "9a855e0f55d16f42761e9a0d05040643be5867f6"
            }
          ],
          "repo": "https://github.com/mikro-orm/mikro-orm",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-qpfv-44f3-qqx6"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-1321"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34221.json"
  },
  "details": "MikroORM is a TypeScript ORM for Node.js based on Data Mapper, Unit of Work and Identity Map patterns. Prior to versions 6.6.10 and 7.0.6, a prototype pollution vulnerability exists in the Utils.merge helper used internally by MikroORM when merging object structures. The function did not prevent special keys such as __proto__, constructor, or prototype, allowing attacker-controlled input to modify the JavaScript object prototype when merged. This issue has been patched in versions 6.6.10 and 7.0.6.",
  "id": "CVE-2026-34221",
  "modified": "2026-04-01T23:09:01.936596242Z",
  "published": "2026-03-31T15:17:45.286Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34221.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/mikro-orm/mikro-orm/security/advisories/GHSA-qpfv-44f3-qqx6"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-34221"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:L/SA:L",
      "type": "CVSS_V4"
    }
  ],
  "summary": "MikroORM has Prototype Pollution in Utils.merge"
}