GitHub Advisoryadvisory · npm
GHSA-2vcc-5v34-9jc8 TinaCMS rich-text (slatejson) rendering does not sanitize link/image URLs, allowing stored XSS via dangerous URL schemes
MEDIUM
Official page ↗
- Aliases
- CVE-2026-55661
- Ecosystem
- npm
- Packages
- tinacms, @tinacms/mdx
- Severity
- Moderate
- CVSS vector
- CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
- Weaknesses
- CWE-79, CWE-87
- Reviewed
- 2026-06-18
Affected packages
• npm tinacms: < 3.9.3 → fixed in 3.9.3
• npm @tinacms/mdx: < 2.1.7 → fixed in 2.1.7
Description
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.
Related
Alias · CVE (1)
- CVE-2026-55661 Tina is a headless content management system. vulnerability