CVE-2026-55661
TinaCMS rich-text (slatejson) rendering does not sanitize link/image URLs, allowing stored XSS via dangerous URL schemes
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.
How to fix CVE-2026-55661
To remediate CVE-2026-55661, upgrade the affected package to a fixed version below.
- —upgrade to 3.9.3 or later
- —upgrade to 2.1.7 or later
Is CVE-2026-55661 being exploited?
No exploitation signal available. Neither CISA KEV nor a current EPSS score has been published for CVE-2026-55661.
Affected packages (2)
- from 0, < 3.9.3
- from 0, < 2.1.7
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | 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 |