CVE-2026-53948

Ghost: File Upload Content-Type Spoofing

State: Published
Severity: 5.4 Medium
Published: Jun 24, 2026
Updated: Jun 25, 2026
Reserved: Jun 11, 2026

Description

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.

Scores

CVSS	Score	Vector	Source
3.1	5.4 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N	GitHub_M

Weaknesses

CWE-434 Unrestricted Upload of File with Dangerous Type

Affected Products

Product	Versions
GhostTryGhost	>= 6.19.4, < 6.21.1Affected

References

https://github.com/TryGhost/Ghost/security/advisories/GHSA-944x-pm95-3jpr

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