Typebot is a chatbot builder tool. In versions 3.15.2 and prior, the RatingButton component in the embed package renders the user-controlled customIcon.svg field directly via Solid's innerHTML directive without any sanitization, even though DOMPurify is already a dependency and is used elsewhere in the codebase (e.g., StreamingBubble.tsx). Because rating blocks are not flagged as isUnsafe by the import sanitizer and the builder preview renders bots inline on the builder's own origin (builder.typebot.io) under a CSP permitting 'unsafe-inline', a malicious imported or collaborator-crafted typebot can execute arbitrary HTML/JS in the builder's authenticated context, bypassing the Web Worker sandbox that protects Script blocks during preview. This allows session hijacking and privilege escalation within the builder application. This issue has been fixed in version 3.16.0.

Affected: npm: @typebot.io/js

## Summary The rating block's custom icon feature accepts arbitrary HTML/SVG via the `customIcon.svg` field and renders it using Solid's `innerHTML` directive without any sanitization. When a malicious typebot is imported or crafted by a workspace collaborator, the payload executes in the builder's DOM context (builder.typebot.io), bypassing the `isUnsafe` Web Worker sandbox that protects Script blocks during preview. This allows session hijacking and privilege escalation within the builder application.

## Severity **High** (CVSS 3.1: 8.7)

`CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N`

- **Attack Vector:** Network — malicious typebot can be delivered via import/template sharing or crafted by a collaborator - **Attack Complexity:** Low — payload is a trivial HTML injection, no special conditions required - **Privileges Required:** Low — attacker needs either collaborator access to a workspace or the ability to distribute a typebot template - **User Interaction:** Required — victim must preview the bot in the builder - **Scope:** Changed — the vulnerable component (embed JS rating renderer) impacts the builder application's authentication context, a different security scope - **Confidentiality Impact:** High — full access to builder session cookies, auth tokens, and API access - **Integrity Impact:** High — can modify bots, workspace settings, or perform any action as the victim user - **Availability Impact:** None — no denial of service vector

- **Builder preview context…