GitHub Advisoryadvisory · npm
GHSA-qpfv-44f3-qqx6 MikroORM has Prototype Pollution in Utils.merge
HIGH
Official page ↗
- Aliases
- CVE-2026-34221
- Ecosystem
- npm
- Packages
- @mikro-orm/core
- Severity
- High
- CVSS 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
- Weaknesses
- CWE-1321
- Reviewed
- 2026-03-29
Affected packages
• npm @mikro-orm/core: < 6.6.10 → fixed in 6.6.10
• npm @mikro-orm/core: >= 7.0.0-dev.0, < 7.0.6 → fixed in 7.0.6
Description
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.
Related
Alias · CVE (1)
- CVE-2026-34221 MikroORM is a TypeScript ORM for Node.js based on Data Mapper, Unit of Work and Identity Map patterns. vulnerability
Weakness · CWE (1)
- CWE-1321 Improperly Controlled Modification of Object Prototype Attributes weakness