GitHub Advisoryadvisory · npm

GHSA-qpfv-44f3-qqx6 MikroORM has Prototype Pollution in Utils.merge

HIGH Published 2026-03-29 Modified 2026-03-31 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

References