CVE-2026-89093: Better Messages <= 2.15.33 - Unauthenticated Information Exposure Spoofing via 'X-Real-IP' Header via /guests/register

The Better Messages – Chat Rooms, Group Chat, Private Messages & AI Chat Bots plugin for WordPress is vulnerable to Information Exposure by Spoofing in all versions up to, and including, 2.15.33. This is due to the isaibotuser() function identifying privileged internal AI bot accounts by performing a prefix check for 'ai-chat-bot-' against a guest record's stored IP address, which is populated verbatim from the client-controlled X-Real-IP request header during unauthenticated guest registration. This makes it possible for unauthenticated attackers to register a guest identity that the plugin treats as its own internal AI bot, bypassing the per-room role allowlist, draft-status check, and join filters — which are all short-circuited by the bot check in usercanjoin() and usercanread() — to join administrator-restricted chat rooms, post messages into them, and read the private message history of other users.