CVE-2026-96297: MongoDB Server may disclose process memory via a crafted `$_internalApplyOplogUpdate` aggregation pipeline
Use of freed memory in the aggregation feature of MongoDB Server can cause the server to read data from a memory area after it has been released. When an internal aggregation stage is combined with a batch size of 0, the server may read from memory that is no longer in use. Because that memory can be reused for other data before it is read, query results returned to the client may contain unrelated data from the server process. Depending on the state of memory at the time, the server process may also terminate unexpectedly. The behavior can occur when an authenticated user with read privileges runs an aggregate command that combines these two settings.
Affected Software
Event History
Frequently Asked Questions
Who can exploit this issue?
An authenticated MongoDB user with read privileges can trigger the issue. The attack is network-accessible and does not require user interaction.
What request conditions are required to trigger the behavior?
The user must run an aggregate command that combines the internal $_internalApplyOplogUpdate aggregation stage with a batch size of 0. Under those conditions, the server may read freed memory and return unrelated process data in query results.
What is the potential impact beyond data disclosure?
Query results may include unrelated data from the MongoDB server process, depending on memory reuse at the time of the read. The server process may also terminate unexpectedly.