It was reported that it is possible for remote unauthenticated attackers to cause the host to kill mongoDB service due to memory exhaustion. This issue can be triggered by making multiple database creation requests. Even if authentication fails, the requested database is created in memory. Eventually, the host runs out of memory and kills Mongo service resulting in a denial of service. After service restart, all created databases are deleted.
The issue was identified in versions 2.4 and 2.6. The issue was found to be not reproducible on 3.0.11 and 3.2.4.
Name: Simon Budail Essard, Philippe Jacquot
Note on exploitation on mongodb-2.6:
This issue does not affect all MongoDB 2.6 installations; it only
affects MongoDB 2.6 installations in circumstances where they first had a
MongoDB 2.4 installation with authentication enabled, upgraded to 2.6, and
did not complete a full upgrade (i.e., did not migrate the
authuser-schema). More details are provided in the above SERVER ticket.