Mongoid Unsafe Reflection Enables Unintended Method Calls
CVE-2026-93765 Published on September 18, 2026
Document deletion and process crash via unvalidated method-name dispatch in atomic pop operation
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.
Vulnerability Analysis
CVE-2026-93765 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
What is a Reflection Injection Vulnerability?
The application uses external input with reflection to select which classes or code to use, but it does not sufficiently prevent the input from selecting improper classes or code. If the application uses external inputs to determine which class to instantiate or which method to invoke, then an attacker could supply values to select unexpected classes or methods. If this occurs, then the attacker could create control flow paths that were not intended by the developer. These paths could bypass authentication or access control checks, or otherwise cause the application to behave in an unexpected manner. This situation becomes a doomsday scenario if the attacker can upload files into a location that appears on the application's classpath (CWE-427) or add new entries to the application's classpath (CWE-426). Under either of these conditions, the attacker can use reflection to introduce new, malicious behavior into the application.
CVE-2026-93765 has been classified to as a Reflection Injection vulnerability or weakness.
Affected Versions
MongoDB Inc. Mongoid:- Version 9.1.0 is affected.
- Version 9.0.0, <= 9.0.11 is affected.
- Version 8.1.0, <= 8.1.12 is affected.
- Version 8.0.0, <= 8.0.12 is affected.