AIKIDO-2026-392862
@mikro-orm/core is vulnerable to Prototype Pollution
65
Medium Risk
This Affects:
@mikro-orm/coreTL;DR
The EntityLoader.mergeNestedPopulate() method in the core package uses populate hints without validating their property names. When an application forwards untrusted options into a query, a populate hint using a reserved name such as __proto__ with a nested children array triggers unsafe mutation of the global Object.prototype. This corrupts the prototype process-wide, causing denial of service and cross-request or cross-tenant logic corruption. The fix rejects reserved property names and uses own-property checks via Object.hasOwn when traversing populate hints and active filters.
Who does this affect?
You are affected if you are using a version that falls within the vulnerable range and your application forwards untrusted options into entity population.
Background info
@mikro-orm/core is vulnerable to Prototype Pollution in versions 4.0.4 - 7.1.11.
How to fix this
Upgrade the @mikro-orm/core library to the patch version.
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SOC 2Compliant
ISO 27001Compliant