MongoDB Go Driver BulkWrite DB Name Separator Injection
CVE-2026-81521 Published on August 27, 2026
Cross-database write retargeting via unvalidated dotted database name in Client.BulkWrite in the MongoDB Go Driver
The MongoDB Go Driver's client-level bulk write operation may accept a caller-supplied database name containing a reserved separator character without escaping it before the name is used to build the target namespace for the operation. An application that passes untrusted input as a database name could therefore have the write directed at a database and collection other than the ones it intended. Only the Client.BulkWrite API is affected.
Vulnerability Analysis
CVE-2026-81521 can be exploited with network access, and requires small amount of user privileges. 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 an Insecure Direct Object Reference Vulnerability?
The software receives input from an upstream component, but it does not restrict or incorrectly restricts the input before it is used as an identifier for a resource that may be outside the intended sphere of control.
CVE-2026-81521 has been classified to as an Insecure Direct Object Reference vulnerability or weakness.
Affected Versions
MongoDB GO Driver:- Version 2.1.0 and below 2.8.2 is affected.