---
id: CVE-2026-55661
title: >-
  TinaCMS rich-text (slatejson) rendering does not sanitize link/image URLs,
  allowing stored XSS via dangerous URL schemes
summary: >-
  TinaCMS rich-text (slatejson) rendering does not sanitize link/image URLs,
  allowing stored XSS via dangerous URL schemes
severity: medium
cwe:
  - CWE-79
  - CWE-87
vendor: tinacms
product: tinacms
ecosystem: npm
affected:
  - tinacms < 3.9.3
  - '@tinacms/mdx < 2.1.7'
patched:
  - tinacms 3.9.3
  - '@tinacms/mdx 2.1.7'
published: '2026-06-18'
updated: '2026-06-18'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-2vcc-5v34-9jc8'
references:
  - url: 'https://github.com/tinacms/tinacms/security/advisories/GHSA-2vcc-5v34-9jc8'
  - url: 'https://github.com/tinacms/tinacms/pull/7056'
  - url: 'https://github.com/advisories/GHSA-2vcc-5v34-9jc8'
tags:
  - ghsa
  - npm
ingestedAt: '2026-06-29T14:31:47.000Z'
epss: 0.00405
epssPercentile: 0.3203
---

## Overview

TinaCMS rich-text parsing and the default link/image renderers did not sanitize the `url` field on Slate link/image nodes. Content containing `javascript:` or `data:text/html` URLs — including case-variant, whitespace-padded, and control-character-obfuscated forms — is rendered into `href`/`src` and executes when the content is viewed. Any actor able to author rich-text content (for example a lower-privileged editor, or imported/external content) can achieve stored XSS against editors and site viewers.

Fixed in https://github.com/tinacms/tinacms/pull/7056 via a `sanitizeUrl()` helper (case-insensitive, whitespace/control-character-normalized scheme allow-list) applied recursively to Slate trees at parse time and in the default rich-text rendering.

## Affected packages

- `tinacms < 3.9.3`
- `@tinacms/mdx < 2.1.7`

## Remediation

Upgrade to a patched release:

- `tinacms 3.9.3`
- `@tinacms/mdx 2.1.7`