Vulnerability · Published Oct 22, 2026 · Assigned by mongodb
CVE-2026-114646NoSQL command injection via mismatched raw BSON length prefix written verbatim to the wire
Medium 6.5
In plain English
A medium-severity security flaw in C# Driver from MongoDB. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 18% of all known vulnerabilities).
Official description
A data-validation flaw exists in the BSON handling and binary serialization path of the MongoDB C# Driver. When an application constructs a raw or lazy BSON document object from externally supplied binary data, the driver does not verify that the size quantity declared inside that data matches the amount of data actually provided, and it copies the data onto the wire unchanged. An unauthenticated party who can supply binary content to such an application can thereby cause additional elements to be inserted into, or existing elements to be removed from, the database command the application issues, without needing any database credentials of their own. This can result in unauthorized modification of stored data and disclosure of data outside the intended scope of the application's request, bounded by the database privileges the application itself holds.
Affected products (as reported)
Weakness: CWE-130 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N