Executive brief
TypeBot is a chatbot builder tool used to create and embed interactive chat interfaces on websites. A security flaw allows malicious bot authors to embed hidden JavaScript code within chat bubbles. If a visitor clicks a link in the chatbot, the attacker's code can run in the visitor's browser, potentially stealing login session tokens or sensitive data from the website where the chatbot is hosted.
Technical details
A stored cross-site scripting (XSS) vulnerability exists in the Typebot viewer (packages/embeds/js) due to insufficient URI scheme filtering in rich text bubbles. The vulnerable components, specifically PlateBlock.tsx and ImageBubble.tsx, render anchor tags using the 'href' attribute directly from user-supplied content without neutralizing the 'javascript:' scheme. An authenticated attacker (including free-tier users) can create a bot containing a malicious payload. When a victim interacts with the resulting chatbot and clicks the link, the JavaScript executes within the context of the host page's origin. This allows for the exfiltration of cookies and session tokens. The issue is resolved in version 3.16.0 by implementing URI filtering.
Affected products
- baptisteArno typebot.io < 3.16.0
Timeline
- 2026-05-22: disclosed
- 2026-05-22: advisory
- 2026-04-08: patched: Release v3.16.0 published