CVE-2026-89093 describes an improper authentication vulnerability (CWE-287) in the Better Messages – Chat Rooms, Group Chat, Private Messages & AI Chat Bots WordPress plugin. The vulnerability arises because the is_ai_bot_user() function identifies privileged AI bot users by checking if the stored IP address starts with 'ai-chat-bot-'. This IP address is taken verbatim from the client-controlled X-Real-IP HTTP header during unauthenticated guest registration. Consequently, an attacker can register a guest identity with a crafted X-Real-IP header to impersonate an internal AI bot. This bypasses the plugin's per-room role allowlist, draft-status checks, and join filters, allowing unauthorized access to administrator-restricted chat rooms, posting messages, and reading private message histories.

An unauthenticated attacker can impersonate internal AI bot accounts, bypassing access controls to join restricted chat rooms, post messages, and read private messages of other users. The confidentiality of private message histories is compromised. There is no indication of integrity or availability impacts. The CVSS score of 5.3 reflects a medium severity with network attack vector, low attack complexity, no privileges required, and no user interaction needed.

No official patch or fix is currently documented. Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until a fix is available, restrict or monitor usage of the plugin and consider disabling guest registrations or filtering the X-Real-IP header to prevent spoofing. Avoid relying on client-controlled headers for authentication or privilege checks.