MongoDB C# Driver NoSQL Injection in Aggregation Translation
CVE-2026-81527 Published on August 27, 2026

NoSQL injection via unquoted constant GroupBy keys in LINQ pipeline translation
A NoSQL/expression injection weakness exists in the LINQ-to-aggregation query translation layer of the MongoDB C# Driver, in both aggregation expression and query filter translation. When application-supplied values are embedded in certain query constructs, special elements contained within those values are not properly escaped before the resulting query is transmitted to the database, so portions of the value may be interpreted by the database as query logic rather than as data. A user able to supply values that an application incorporates into an affected query may thereby cause unintended data to be returned or query results to be altered.

NVD

Vulnerability Analysis

CVE-2026-81527 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.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE

Weakness Type

Improper Neutralization of Special Elements in Data Query Logic

The application generates a query intended to access or manipulate data in a data store such as a database, but it does not neutralize or incorrectly neutralizes special elements that can modify the intended logic of the query.


Products Associated with CVE-2026-81527

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MongoDB C Driver
 

Affected Versions

MongoDB C# Driver: