Typebot: Stored XSS via Rating Block Custom Icon Bypasses isUnsafe Sandbox in Builder Preview

published 2026-05-22 5 mo ago modified 2026-09-10 1 mo ago also EUVD-2026-31466 , GHSA-6m7c-xfhp-p9fh

cvss: 8.7; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.3%; EPSS 0.3% chance of exploitation in 30 days, percentile 17%
public exploits: 0; none known

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.

Patch / fix

fixed in 2 links 2

npm @typebot.io/js 0.10.1
typebot typebot 3.16.0

CISA SSVC

Exploitation: Proof of concept is public
Automatable: no
Technical impact: partial
Assessed: 5 mo ago (2026-05-22)

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/baptisteArno/typebot.io/security/advisories/GHSA-6m7c-xfhp-p9fh referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CNA	3.1	8.7	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N
GitHub	3.1	8.7	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
npm	@typebot.io/js	<0.10.1	0.10.1

Affected products

baptisteArno typebot.io

Classification

Weakness

CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary