There is stored cross site scripting in the wp-live-chat-support plugin before 8.0.08 for WordPress via the "name" (aka wplc_name) and "email" (aka wplc_email) input fields to wp-json/wp_live_chat_support/v1/start_chat whenever a malicious attacker would initiate a new chat with an administrator. NOTE: this issue exists because of an incomplete fix for CVE-2018-9864.
https://wordpress.org/plugins/wp-live-chat-support/#developers
https://github.com/RiieCco/write-ups/tree/master/CVE-2018-11105