CVE-2026-53948: Tryghost Ghost

Medium severity, CVSS 5.4. EPSS: 0.2% chance of exploitation in the next 30 days.

Ghost is a Node.js content management system. From 6.19.4 until 6.21.1, insufficient validation of the client-supplied Content-Type on Ghost's Admin API file upload endpoint allowed uploaded files to be served from the site with an attacker-chosen content type on S3/GCS storage backends. On installations that serve uploaded files from the same origin as the site, this could have been used to facilitate stored cross-site scripting against site visitors or staff. This vulnerability is fixed in 6.21.1.

Affected products

• Tryghost Ghost: from 6.19.4, before 6.21.1 (fixed in 6.21.1)

Published 2026-06-24. Last modified 2026-06-25.