Moodle 1.9.x before 1.9.18, 2.0.x before 2.0.9, 2.1.x before 2.1.6, and 2.2.x before 2.2.3 allows remote authenticated users to bypass the moodle/calendar:manageownentries capability requirement and add a calendar entry via a New Entry action.
Exploitability
AV:NAC:LAu:SImpact
C:NI:PA:N4/AV:N/AC:L/Au:S/C:N/I:P/A:N