🛡️ CVE-2026-53948 — ghost

🟡 CVSS 5.4 — Medium ✅ No Known Exploit CWE-434 NVD
5.4
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Ghost: File Upload Content-Type Spoofing

Impact

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.

Vulnerable versions

This vulnerability is present in Ghost from v6.19.4 up to v6.21.0.

Patches

v6.21.1 contains a fix for this issue.

How to update

For self-hosters using Docker, find [Docker's official Ghost image here](https://hub.docker.com/_/ghost). Updating a Docker-based Ghost instance [is documented here](https://docs.ghost.org/install/docker#updating-ghost).

If your Ghost is a Ghost-CLI install see our documentation on [updating it to the latest version here](https://docs.ghost.org/update).

For more information

If you have any questions or comments about this advisory, email us at [security@ghost.org](mailto:[email protected]).

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs low-level privileges on the target. A user must be tricked into taking some action. The scope is changed, meaning a successful attack can affect components beyond the vulnerable one. Rated impact: confidentiality low, integrity low, availability none.

Weakness class

CVE-2026-53948 is classified as CWE-434: Unrestricted Upload of File with Dangerous Type. Uploads are accepted without restricting type, so an executable file can be placed where the server will run it.

Affected software

CVE-2026-53948 is recorded against 2 packages.

  • ghost
  • unknown

Timeline and source

Published on 30 June 2026 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from NVD.

References

github.com (Web)
nvd.nist.gov (Web)

Details

Severity MEDIUM
CVSS Score 5.4
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CWE CWE-434
Public Exploit ✅ No
Source NVD
Published 2026-06-30
Updated 2026-08-12
Modified 2026-08-04
Fix URL N/A

Affected Packages

Software From version Fixed in
ghost — —
unknown — —

Similar Threats

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