A low privilege (regular) Zabbix user with API access can use SQL injection vulnerability in include/classes/api/CApiService.php to execute arbitrary SQL commands via the groupBy parameter.
The Zabbix API host.get action can be exploited by authenticated users to extract a host's PSK key leading to potential loss of data integrity.
Zabbix API user.get returns all users that share common group with the calling user. This includes media and other information, such as login attempts, etc.
Due to a bug in Zabbix API, the hostprototype.get method lists all host prototypes to users that do not have any user groups assigned to them.