The Item history widget (in Zabbix 7.0+) or the Plain text widget (in Zabbix 6.0) can execute injected JavaScript when HTML display is enabled. This can allow an attacker to perform unauthorized actions depending on which user opens a dashboard containing these widgets. The malicious JavaScript would have to come from a monitored host controlled by the attacker. Note: the Item history widget is a replacement for the Plain text widget since Zabbix 7.0.
An attacker controlled monitored host can send in malicious JavaScript payload that is then executed by the Item history/Plain text widget.
Do not use HTML display in Item history/Plain text widget or disable this widget entirely in Administration -> General -> Modules (Zabbix 7.0+).
Update the affected components to their respective fixed versions.