Zabbix Server and Proxy accept the active agent heartbeat message regardless of the configured PSK or certificate authentication. This means someone with access to the Zabbix trapper port can report an arbitrary host using an active agent as available, resulting in a loss of integrity.

The Zabbix Server/Proxy has a vulnerability where binary items can crash the Server/Proxy on certain NULL byte input leading to potential loss of availability. This only affects deployments where MySQL/MariaDB database is used as the Zabbix database.

An authenticated administrator is able to crash Zabbix server or proxy by creating specifically crafted preprocessing/script item JavaScript scripts, leading to potential denial of service.

For performance reasons Zabbix Server/Proxy reuses JavaScript (Duktape) contexts (used in script items, JavaScript reprocessing, Webhooks). This can lead to confidentiality loss where a regular (non-super) Zabbix administrator leaks data for hosts they do not have access to. A fix has been released that makes the built in Zabbix JavaScript objects read-only, but please be advised that usage of global JavaScript variables is not recommended because their content could be leaked. More information <a href='https://www.zabbix.com/documentation/7.4/en/manual/installation/knownissues#preprocessing-global-variables-are-unsafe'>in Zabbix documentation</a>.