The default configuration for MongoDB before 2.3.2 does not validate objects, which allows remote authenticated users to cause a denial of service (crash) or read system memory via a crafted BSON object in the column name in an insert command, which triggers a buffer over-read.
https://bugzilla.redhat.com/show_bug.cgi?id=1049748
http://www.openwall.com/lists/oss-security/2014/01/08/9
http://www.openwall.com/lists/oss-security/2014/01/07/2
http://www.openwall.com/lists/oss-security/2014/01/07/13