CVE-2026-53948
MediumCVSS 5.4Exploitation Probability (EPSS)
Low risk3th percentile — higher than 3% of all known CVEs
Summary
Ghost is a Node.js content management system. From versions 6.19.4 to 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 with an attacker-chosen content type from S3/GCS storage backends.
Risk Assessment
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.
Recommendation
It is recommended to upgrade to version 6.21.1, where this vulnerability has been fixed.
Original NVD description (English source)
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.