CVE-2026-28445: Typebot has Stored XSS via Rating Block Custom Icon that Bypasses isUnsafe Sandbox in Builder Preview

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.