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GHSA-2vcc-5v34-9jc8

TinaCMS rich-text (slatejson) rendering does not sanitize link/image URLs, allowing stored XSS via dangerous URL schemes

Source: GitHub Advisory Database (reviewed) Moderate CVE-2026-55661

Packages

EcosystemPackageAffectedFixed in
npm tinacms < 3.9.3 3.9.3
npm @tinacms/mdx < 2.1.7 2.1.7

Details

As written in the advisory (Markdown source, shown as plain text).

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.

References

External links from the advisory. They lead to third-party sites.