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.
The endpoint /zabbix.php?action=export.valuemaps suffers from a Cross-Site Scripting vulnerability via the backurl parameter. This is caused by the reflection of user-supplied data without appropriate HTML escaping or output encoding. As a result, a JavaScript payload may be injected into the above endpoint causing it to be executed within the context of the victim's browser.
Zabbix server is vulnerable to a DoS vulnerability due to uncontrolled resource exhaustion. An attacker can send specially crafted requests to the server, which will cause the server to allocate an excessive amount of memory and perform CPU-intensive decompression operations, ultimately leading to a service crash.
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.
When exporting media types, the password is exported in the YAML in plain text. This appears to be a best practices type issue and may have no actual impact. The user would need to have permissions to access the media types and therefore would be expected to have access to these passwords.
The HttpRequest object allows to get the HTTP headers from the server's response after sending the request. The problem is that the returned strings are created directly from the data returned by the server and are not correctly encoded for JavaScript. This allows to create internal strings that can be used to access hidden properties of objects.