CVE-2026-39964CWE-79

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

Medium · published May 22, 2026

CVSS v3.1
5.4
EPSS
0%
Percentile
25.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.4 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00334 · 25.5th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2026-05-22T17:21Z
EPSS history
Timeline
  • 22 MAY 17:21Z
    TypeBot: Stored XSS via javascript: URI in text bubble links — bot author executes JS on visitors' browsers
    cvelistv5