Overview
The Citizen MediaWiki skin, an extension that enhances the visual experience of MediaWiki users, has recently been identified with a significant vulnerability. This security flaw, designated CVE-2025-53370, exposes systems to potential compromise and data leakage. The vulnerability affects versions 1.9.4 to 3.4.0 of the Citizen skin, and is a matter of grave concern for any organization or individual using this particular skin for their MediaWiki sites. The vulnerability has serious implications, making it a high priority issue that should be addressed immediately by all users.
Vulnerability Summary
CVE ID: CVE-2025-53370
Severity: High (8.6)
Attack Vector: Web-based
Privileges Required: None
User Interaction: Required
Impact: System compromise and potential data leakage
Affected Products
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Product | Affected Versions
Citizen MediaWiki Skin | 1.9.4 to 3.4.0
How the Exploit Works
The exploit takes advantage of a flaw in the Citizen MediaWiki skin. The skin, when used with the ShortDescription extension, inserts short descriptions as raw HTML. This allows any user to insert arbitrary HTML into the Document Object Model (DOM) of a page by simply editing it. This could allow an attacker to inject malicious scripts, which could lead to system compromise or data leakage.
Conceptual Example Code
Here is a conceptual example of how the vulnerability might be exploited:
<!-- This is a simple example of how an attacker might inject malicious code -->
<!-- The attacker edits a page's short description and adds a script tag with malicious JavaScript -->
<!-- This script gets executed when the page is loaded -->
SHORT_DESCRIPTION = "<script>malicious_code();</script>"The malicious code could perform a variety of harmful actions, such as stealing sensitive data or taking control of the user’s session.
Mitigation
A patch for this vulnerability has been released in version 3.4.0 of the Citizen MediaWiki Skin. All users are strongly urged to apply this patch immediately. If immediate patching is not possible, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can offer temporary mitigation by detecting and blocking attempts to exploit this vulnerability.