{"id":"CVE-2026-34221","aliases":["EUVD-2026-17488","GHSA-qpfv-44f3-qqx6"],"status":"published","title":"MikroORM has Prototype Pollution in Utils.merge","description":"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.","severity":{"version":"4.0","score":8.3,"vector":"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00383,"percentile":0.32771,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-1321"],"published":"2026-03-29T15:44:16Z","modified":"2026-10-28T02:31:11Z","fixes":[{"ecosystem":"npm","package":"@mikro-orm/core","fixed_in":["6.6.10","7.0.6"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"@mikro-orm/core","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.6.10"}]}]},{"source":"ghsa","ecosystem":"npm","package":"@mikro-orm/core","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"7.0.0-dev.0"},{"fixed":"7.0.6"}]}]},{"source":"osv","ecosystem":"npm","package":"@mikro-orm/core","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"6.6.10"}]}]},{"source":"osv","ecosystem":"npm","package":"@mikro-orm/core","ranges":[{"type":"SEMVER","events":[{"introduced":"7.0.0-dev.0"},{"fixed":"7.0.6"}]}]}],"products":[{"vendor":"mikro-orm","product":"mikro-orm"},{"vendor":"mikro-orm","product":"mikroorm"}],"references":[{"url":"https://github.com/mikro-orm/mikro-orm/security/advisories/GHSA-qpfv-44f3-qqx6","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34221","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-qpfv-44f3-qqx6"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34221.json","tags":["advisory"]},{"url":"https://github.com/mikro-orm/mikro-orm","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-34221","title":"MikroORM has Prototype Pollution in Utils.merge","description":"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.","status":"published","published":"2026-03-31T15:17:45.286Z","modified":"2026-03-31T18:52:43.939Z","cvss":[{"version":"4.0","score":8.3,"vector":"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","level":"high","assessor":"cna"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T14:20:14.302133Z"}],"euvd":[{"id":"EUVD-2026-17488","description":"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.","status":"published","published":"2026-03-31T15:17:45Z","modified":"2026-03-31T18:52:43Z","cvss":[{"version":"4.0","score":8.3,"vector":"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","level":"high"}],"updated_at":"2026-11-02T19:25:24.891983Z"}],"ghsa":[{"id":"GHSA-qpfv-44f3-qqx6","title":"MikroORM has Prototype Pollution in Utils.merge","description":"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.","status":"published","published":"2026-03-29T15:44:16Z","modified":"2026-03-31T18:55:11Z","cvss":[{"version":"4.0","score":8.3,"vector":"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","level":"high"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T14:39:47.075804Z"}],"nvd":[{"id":"CVE-2026-34221","description":"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.","status":"published","published":"2026-03-31T16:16:32.293Z","modified":"2026-07-24T20:10:00.147Z","cvss":[{"version":"4.0","score":8.3,"vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H","level":"critical","assessor":"primary"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T14:12:12.261218Z"}],"osv":[{"id":"CVE-2026-34221","title":"MikroORM has Prototype Pollution in Utils.merge","description":"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.","status":"published","published":"2026-03-31T15:17:45.286Z","modified":"2026-10-28T02:31:11.300552902Z","cvss":[{"version":"4.0","score":8.3,"vector":"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","level":"high"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T15:45:02.247031Z"},{"id":"GHSA-qpfv-44f3-qqx6","title":"MikroORM has Prototype Pollution in Utils.merge","description":"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.","status":"published","published":"2026-03-29T15:44:16Z","modified":"2026-03-31T19:04:39.043387Z","cvss":[{"version":"4.0","score":8.3,"vector":"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","level":"high"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T15:46:54.760124Z"}]}}