Better Messages <= 3.0.4 - Authenticated (Subscriber+) Stored DOM-Based Cross-Site Scripting via User Display Name

The Better Messages – Chat Rooms, Group Chat, Private Messages & AI Chat Bots plugin for WordPress is vulnerable to Stored DOM-Based Cross-Site Scripting via User Display Name in all versions up to, and including, 3.0.4 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with subscriber-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This is exploitable by Subscriber-level users because WordPress core's sanitize_text_field() preserves HTML-entity-encoded payloads (e.g., an iframe srcdoc attribute), allowing the encoded string to be stored as a display name without requiring the unfiltered_html capability, and the plugin subsequently decodes it server-side before rendering.

An attacker needs Subscriber access first, so the firewall sees the attempt as traffic from a logged-in account: WordSec's web application firewall inspects request payloads before WordPress loads them. None of that substitutes for the fix: Better Messages 3.0.5 closes this, and updating the plugin is the step that ends it.

• Firewall
• Alerts