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GHSA-g5qx-h5f3-mp2f

HighCVSS 8.5 / 10
Published Jun 19, 2026·Last modified Jun 19, 2026
Affected Components(0)

No affected components available

Description

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 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 previously bundled here has been split into its own advisory (GHSA-2vcc-5v34-9jc8) so each vulnerability can receive a distinct CVE.

Risk Scores
Base Score
8.5

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights.

Threat Intelligence
6.0

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.20%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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