GHSA-r7f2-6fj8-6fg2: SSRF
Impact
A validation issue allowed some functionality, such as Webmentions, to be abused by an unauthenticated user to make limited HTTP requests to hosts in the Ghost server's internal network on some network configurations. A successful attack would not result in any response data being returned.
Vulnerable versions
This vulnerability is present in Ghost from v6.0.9 up to v6.64.0.
Patches
v6.65.0 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 Nhat Anh Vu 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 6.65.0 - Upgrade
Upgrade
Ghostto a version that resolves this vulnerability.Fixed in 6.65.0
Event History
Frequently Asked Questions
Which deployments are affected?
Ghost versions from 6.0.9 through 6.64.0 are affected. Exploitability depends on the server's network configuration, because the issue concerns requests to hosts reachable on Ghost's internal network.
Does an attacker need an account or user interaction?
No. The advisory states that an unauthenticated attacker can abuse affected functionality, including Webmentions, without requiring user interaction. Exploitation has high attack complexity.
What can an attacker obtain through the issue?
An attacker can cause limited HTTP requests to internal-network hosts. Response data is not returned, so the issue does not directly expose the content of those responses.
What is the remediation?
Upgrade Ghost to version 6.65.0, which contains the fix. The advisory provides update paths for both Docker-based and Ghost-CLI installations.