CVE-2026-28445
Typebot: Stored XSS via Rating Block Custom Icon Bypasses isUnsafe Sandbox in Builder Preview
Description
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.
INFO
Published Date :
May 22, 2026, 4:12 p.m.
Last Modified :
May 22, 2026, 4:12 p.m.
Remotely Exploit :
No
Source :
GitHub_M
Affected Products
The following products are affected by CVE-2026-28445
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
Solution
- Update Typebot to version 3.16.0 or later.
- Review custom icon sanitization practices.
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The following table lists the changes that have been made to the
CVE-2026-28445 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
May. 22, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N Added CWE CWE-79 Added Reference https://github.com/baptisteArno/typebot.io/commit/474ecbf46bc47a75265bada2599f12b2179de375 Added Reference https://github.com/baptisteArno/typebot.io/releases/tag/v3.16.0 Added Reference https://github.com/baptisteArno/typebot.io/security/advisories/GHSA-6m7c-xfhp-p9fh