CVE-2026-93765: MongoDB Mongoid

Critical severity, CVSS 9.1. EPSS: 0.5% chance of exploitation in the next 30 days.

Mongoid contains an unsafe reflection weakness in the document persistence layer of its object-document mapping code. Input whose keys are passed through from an unauthenticated party by an embedding application can cause unintended internal method invocation instead of the intended array field update. This may result in unintended removal of stored records and in the embedding application becoming unresponsive.

Affected products

• MongoDB Mongoid: from 8.0.0, before 8.0.12 (fixed in 8.0.12); from 8.1.0, before 8.1.13 (fixed in 8.1.13); from 9.0.0, before 9.0.12 (fixed in 9.0.12); version 9.1.0 only

Published 2026-09-18. Last modified 2026-09-25.