CVE-2026-39964 MEDIUM

CVE-2026-39964: TypeBot: Stored XSS via javascript: URI in text bubble links — bot author executes JS on visitors' browsers

Vendor Baptistearno
Product typebot.io
Weakness CWE-79 · XSS
Published May 22, 2026
Last update May 23, 2026

CVSS base score

5.4/10
Attack vector Network
Attack complexity Low
Privileges required Low
User interaction Required
Confidentiality Low
Integrity Low

CVSS vector

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

What the vulnerability does

Description

TypeBot is a chatbot builder tool. In versions prior to 3.16.0, the Typebot viewer (packages/embeds/js) renders anchor tags from rich text bubble content without filtering the javascript: URI scheme. A bot author can set a link URL to javascript:PAYLOAD, which executes in the visitor's browser context when clicked. Since the viewer is typically embedded in a third-party site, the attacker's JavaScript runs in the host page's origin and can exfiltrate cookies and session tokens. This can result in any authenticated Typebot user (including those on the free tier) being able to create a bot with this payload. Shared bots are publicly accessible — no victim authentication is required. This issue has been resolved in version 3.16.0.

Key dates

Disclosure timeline

May 22, 2026 CVE published
May 23, 2026 Record updated