The Streamit WordPress theme through 4.5.0 does not perform any authorization or nonce verification on one of its unauthenticated AJAX routes, which invokes an attacker-supplied PHP function with an attacker-supplied argument array, allowing unauthenticated attackers to call arbitrary functions (for example to create an administrator account), leading to privilege escalation and remote code execution.
https://wpscan.com/vulnerability/f85c5da1-412f-4079-8c44-708bc78c2b9b/