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Prototype pollution in Utils.merge

High
B4nan published GHSA-qpfv-44f3-qqx6 Mar 27, 2026

Package

npm @mikro-orm/core (npm)

Affected versions

<= 6.6.9, 7.x <= 7.0.5

Patched versions

6.6.10, 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.

Severity

High

CVE ID

CVE-2026-34221

Weaknesses

No CWEs

Credits