CVE-2021-29484: DOM XSS in Theme Preview
First published: Thu Apr 29 2021(Updated: )
Ghost is a Node.js CMS. An unused endpoint added during the development of 4.0.0 has left sites vulnerable to untrusted users gaining access to Ghost Admin. Attackers can gain access by getting logged in users to click a link containing malicious code. Users do not need to enter credentials and may not know they've visited a malicious site. Ghost(Pro) has already been patched. We can find no evidence that the issue was exploited on Ghost(Pro) prior to the patch being added. Self-hosters are impacted if running Ghost a version between 4.0.0 and 4.3.2. Immediate action should be taken to secure your site. The issue has been fixed in 4.3.3, all 4.x sites should upgrade as soon as possible. As the endpoint is unused, the patch simply removes it. As a workaround blocking access to /ghost/preview can also mitigate the issue.
Credit: security-advisories@github.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Ghost Ghost Node.js | >=4.0.0<4.3.3 |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2021-29484?
CVE-2021-29484 has been classified as a critical vulnerability due to its potential for unauthorized access to Ghost Admin.
How do I fix CVE-2021-29484?
To fix CVE-2021-29484, update your Ghost instance to a version later than 4.3.3.
What versions of Ghost are affected by CVE-2021-29484?
CVE-2021-29484 affects Ghost versions from 4.0.0 to 4.3.3.
What type of attack is associated with CVE-2021-29484?
CVE-2021-29484 is associated with an attack where untrusted users can gain access to Ghost Admin through malicious links.
Are there any workarounds for CVE-2021-29484?
No official workarounds are recommended for CVE-2021-29484; upgrading to a secure version is the only solution.
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