If you’re running an XWiki-based knowledge base, this post is for you. In November 2022, a major security flaw was reported: CVE-2022-41927. This vulnerability allows an attacker to exploit a Cross-Site Request Forgery (CSRF) to delete or rename tags across your XWiki platform—without needing any user confirmation. If left unpatched, this could be a goldmine for attackers wanting to tamper with your content.

Let’s break it down with simple language, code examples, and steps to fix the issue. All info here is exclusive and easy to understand—even if you’re not a security pro.

What Is CVE-2022-41927?

XWiki Platform (often used for internal docs, wikis, and knowledge bases) had a flaw: attackers could trick logged-in users into clicking a malicious link or visiting a web page. Without further user action, the attack could send requests that delete or rename your tags—even delete important content labels or change organization.

That works because the platform’s tag management system failed to properly verify that requests came from a real, authenticated user action. Normally, systems require a secret “token” to prove a request is genuine. In this case, the check was missing.

Official CVE Entry: CVE-2022-41927 on MITRE  
XWiki Security Advisory: XWIKI-20199

Affected versions:

Here’s what such a malicious request could look like

<!-- CSRF attack: sending a POST to delete a tag without your knowledge -->
<form action="https://your-wiki.example.com/xwiki/bin/delete/Main/Tags"; method="POST" style="display:none">
  <input type="hidden" name="tag" value="important"/>
  <input type="submit" /> 
</form>
<script>
  document.forms[].submit()
</script>

Anyone visiting a page with this code while logged in will send a tag deletion request as *themselves*, and XWiki complies.

The Patch: Token Validation

The correct security measure is to require a special *CSRF token* with every sensitive action. The platform should validate this token before renaming or deleting anything.

The XWiki team’s fix was to add a verification step in the code for deleting and renaming tags. You can manually do this too—even if you can’t upgrade right now!

Quick Manual Patch:

In the scripts handling *delete* and *rename* operations, add the CSRF check as shown below

#if (!$services.csrf.isTokenValid($request.get('form_token')))
  #set ($discard = $response.sendError(401, "Wrong CSRF token"))
#end

What’s happening?

- This code asks the server: “Does the ‘form_token’ sent with this request match a valid token for the current session?”

Here’s a more concrete *attack scenario* for CVE-2022-41927

1. Preparation: An attacker learns the name of important tags in your system (e.g., by browsing public tags or guessing).

`html

https://your-xwiki.com/xwiki/bin/rename/Main/Tags" method="POST" id="evilForm">
     
     
     

document.getElementById('evilForm').submit();

*(Similar for delete.)*

3. Execution: You, a logged-in XWiki editor, visit their site—perhaps via a link, email, or injected ad.
4. Effect: Your browser, still logged in to XWiki, unwittingly sends requests to delete or rename tags.

14.5RC1

Newer versions are safe.

`

Double check all forms that perform sensitive changes use this pattern.

More Resources and References

- Official XWiki announcement: XWiki Security Advisory: XWIKI-20199
- CVE entry: CVE-2022-41927 on MITRE
- CSRF concepts, explained: OWASP - Cross-Site Request Forgery

Final Thoughts

It only takes one missed security update for an attacker to mess with your XWiki tags using CVE-2022-41927. Protect your docs—upgrade your XWiki or patch it with the code above. Always keep an eye on security advisories and double check for basic token checks in custom scripts!

Stay safe. Got questions about patching this bug? Leave a comment or check the links above for more help.

Timeline

Published on: 11/23/2022 19:15:00 UTC
Last modified on: 11/30/2022 16:22:00 UTC