In late 2023, a security vulnerability identified as CVE-2023-4422 was responsibly disclosed in the popular open-source project Cockpit, a headless CMS that lets you manage structured content. The issue was a stored Cross-site Scripting (XSS) bug that existed prior to version 2.6.3, and it had the potential to let malicious users inject harmful scripts into the admin interface.

This post breaks down what happened, how the exploit works, and how to stay protected.

What is CVE-2023-4422?

CVE-2023-4422 is a stored XSS vulnerability in the Cockpit CMS. When untrusted user input is not properly sanitized, attackers can inject JavaScript code that gets stored in the system. Later, when an admin or any user views certain content, the injected code is executed in their browser, leading to potential account compromise or other malicious activities.

Where Was the Flaw?

The vulnerability affected Cockpit versions prior to 2.6.3. Specifically, it stemmed from insufficient escaping when user-supplied data was displayed in the Cockpit admin UI. Anywhere the admin panel rendered data from collections, forms, or entries, the risk was present.

Example: How The XSS Could Be Stored

Suppose your site allows users to submit feedback that's saved in a collection. An attacker could submit the following as a value in a text field:

<script>alert(document.cookie)</script>

If Cockpit failed to escape this value when showing it in the admin dashboard, the script would run whenever an admin viewed the feedback, leaking cookies or taking further actions on the admin's behalf.

Suppose you have a comments collection. An attacker submits a comment with this content

Nice post! <img src=x onerror="alert('XSS')">

When an admin opens the collection in the Cockpit backend, the malicious <img> element triggers the alert.

Here's a simple PoC of exploiting the flaw in the pre-2.6.3 Cockpit environment

Step 1: Submit data via API or form with XSS payload.

curl -X POST https://your-cockpit-instance.com/api/collections/save/comments \
  -H 'Cockpit-Token: API_TOKEN' \
  -H 'Content-Type: application/json' \
  -d '{
    "data": {
      "author": "Attacker",
      "comment": "<img src=x onerror=alert(\"XSS - CVE-2023-4422\")>"
    }
  }'

Step 2: Admin logs in to Cockpit and views the comment. The payload fires in their browser.

Data Theft: Read or manipulate content the admin can access.

- Further Compromise: Potentially gain access to more sensitive areas or install additional malicious payloads.

How Did Cockpit Fix This?

According to the official changelog, input is now sanitized and escaped safely before being rendered in the admin interface. The issue was reported privately and quickly patched.

How To Protect Your Site

1. Upgrade: Apply Cockpit version 2.6.3 or later immediately.

References

- CVE-2023-4422 on NIST NVD
- Cockpit GitHub Repository
- Cockpit Release 2.6.3
- What is Stored XSS? - OWASP

Final Thoughts

CVE-2023-4422 is a strong reminder that every route where user-supplied data is outputted must be carefully handled—especially in admin interfaces that have the keys to your CMS kingdom. Always keep your software up to date and follow secure coding practices.

Have questions? Drop them below or reach out on GitHub!

Timeline

Published on: 08/18/2023 19:15:00 UTC
Last modified on: 08/22/2023 00:58:00 UTC