GHSA-QPFV-44F3-QQX6

Vulnerability from github – Published: 2026-03-29 15:44 – Updated: 2026-03-31 18:55
VLAI?
Summary
MikroORM has Prototype Pollution in Utils.merge
Details

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.

Exploitation requires application code to pass untrusted user input into ORM operations that merge object structures, such as entity property assignment or query condition construction.

Prototype pollution may lead to denial of service or unexpected application behavior. In certain scenarios, polluted properties may influence query construction and potentially result in SQL injection depending on application code.

Severity ?
8.3 (High)
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
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "@mikro-orm/core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.6.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "@mikro-orm/core"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "7.0.0-dev.0"
            },
            {
              "fixed": "7.0.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-34221"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-29T15:44:16Z",
    "nvd_published_at": "2026-03-31T16:16:32Z",
    "severity": "HIGH"
  },
  "details": "A prototype pollution vulnerability exists in the `Utils.merge` helper used internally by MikroORM when merging object structures.\n\nThe function did not prevent special keys such as `__proto__`, `constructor`, or `prototype`, allowing attacker-controlled input to modify the JavaScript object prototype when merged.\n\nExploitation requires application code to pass untrusted user input into ORM operations that merge object structures, such as entity property assignment or query condition construction.\n\nPrototype pollution may lead to denial of service or unexpected application behavior. In certain scenarios, polluted properties may influence query construction and potentially result in SQL injection depending on application code.",
  "id": "GHSA-qpfv-44f3-qqx6",
  "modified": "2026-03-31T18:55:10Z",
  "published": "2026-03-29T15:44:16Z",
  "references": [
    {
      "type": "WEB",
      "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"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mikro-orm/mikro-orm"
    }
  ],
  "schema_version": "1.4.0",
  "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"
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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