CVE-2026-34221 mikro-orm CVE debrief

Who should care

Developers and administrators using MikroORM in their applications should be aware of this vulnerability and take immediate action to update to a patched version. This vulnerability can be exploited by attackers to modify the JavaScript object prototype, potentially leading to security issues. Affected operators, platforms, vulnerability-management, and security teams should review and act on this advisory.

Technical summary

The Utils.merge helper in MikroORM does 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. The vulnerability exists due to the function's inability to prevent special keys such as __proto__, constructor, or prototype. This allows attackers to modify the JavaScript object prototype, potentially leading to security issues.

Defensive priority

High

Recommended defensive actions

• Update MikroORM to version 6.6.10 or 7.0.6
• Review and update affected applications
• Monitor for potential exploitation attempts
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• Review compensating controls for exposed systems while remediation is scheduled and verified.

Evidence notes

The vulnerability was patched in versions 6.6.10 and 7.0.6. Users should update to a patched version to prevent exploitation. This issue allows attacker-controlled input to modify the JavaScript object prototype when merged using the Utils.merge helper. 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. MikroORM, a TypeScript ORM for Node.js, has a prototype pollution vulnerability in versions before 6.6.10 and 7.0.6.

Official resources