CVE-2026-39964

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

MEDIUM
5.4
CVSS Score
Published: May 22, 2026 at 05:21 PM UTC
Updated: July 23, 2026 at 07:32 PM UTC
1 product affected across 1 vendorTypebot

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Severity
MEDIUM5.4
Exploit prediction
EPSS 0.2%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.16.0
Affected range stops below 3.16.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.4MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-79

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