Moodle 2.1.x before 2.1.6 and 2.2.x before 2.2.3 allows remote authenticated users to bypass question:use* capability requirements and add arbitrary questions to a quiz via the questions feature.
http://openwall.com/lists/oss-security/2012/05/23/2
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-32240