An authenticated user without any specific authorizations may be able to repeatedly invoke the features command where at a high volume may lead to resource depletion or generate high lock contention. This may result in denial of service and in rare cases could result in id field collisions.

bson/cbsonmodule.c in the mongo-python-driver (aka. pymongo) before 2.5.2, as used in MongoDB, allows context-dependent attackers to cause a denial of service (NULL pointer dereference and crash) via vectors related to decoding of an "invalid DBRef."