TinaCMS registers window message listeners — the useTina overlay handler, the OAuth authentication popup handler, and the admin↔preview iframe GraphQL reducer — that act on event.data without verifying event.origin or e…
| CVE ID | CVE-2026-55660 |
| Vendor | npm |
| Affected Product | tinacms |
| Vulnerability Type | Vulnerability |
| CVSS Score | 7.5 (HIGH) |
| Actively Exploited | ❌ No known exploitation |
| Patch Status | See Vendor Advisory → |
| Reported By | CYBERDUDEBIVASH SENTINEL APEX Intelligence (via github_advisories) |
TinaCMS registers window message listeners — the useTina overlay handler, the OAuth authentication popup handler, and the admin↔preview iframe GraphQL reducer — that act on event.data without verifying event.origin or event.source, and post messages using non-specific target origins. A page the victim visits (or a window in an opener/iframe relationship with a Tina admin) can forge messages to drive the editor, inject preview content, or observe/forge the OAuth popup channel to take over an authenticated editing session. Fixed in [#7056](https://github.com/tinacms/tinacms/pull/7056) by allow-listing trusted origins and verifying event.source (isFromAdmin, isFromTrustedPreviewOrigin), and by posting only to explicit target origins (never "*"). Note: the rich-text URL-sanitization issue prev
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