GHSA-347q-26qq-h2p6: XSS
Impact
When creating a bookmark card, Ghost could store non-image files fetched from an external website as bookmark icons or thumbnails. This allowed any staff user, including Contributors, to host arbitrary HTML on the site's domain, possibly resulting in compromise of other staff users' admin sessions.
Vulnerable versions
This vulnerability is present in Ghost from v5.94.0 up to v6.64.0.
Patches
v6.64.0 contains a fix for this issue.
How to update
For self-hosters using Docker, find Docker's official Ghost image here. Updating a Docker-based Ghost instance is documented here.
If your Ghost is a Ghost-CLI install see our documentation on updating it to the latest version here.
References
Ghost thanks Thai Son Dinh of VinSOC Labs and 白墨 for disclosing this vulnerability responsibly.
For more information
If you have any questions or comments about this advisory, email us at security@ghost.org.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
npm/ghostto a version that resolves this vulnerability.Fixed in 6.64.0 - Upgrade
Upgrade
Ghostto a version that resolves this vulnerability.Fixed in v6.64.0
Event History
Frequently Asked Questions
Is a low-privilege staff account sufficient to exploit this issue?
Yes. Any staff user, including a Contributor, could trigger the issue by creating a bookmark card that fetches content from an external website.
Which Ghost versions require remediation?
Ghost versions from 5.94.0 up to, but not including, 6.64.0 are affected. Version 6.64.0 contains the fix.
What should self-hosted deployments do to update?
Docker-based deployments should update their Ghost container using the official Ghost image and Docker update procedure. Ghost-CLI installations should use the documented Ghost update process to move to a fixed version.