Overview
A significant security flaw, CVE-2025-53368, has been identified in Citizen, a widely-used skin for the MediaWiki platform. MediaWiki is a scalable open-source wiki platform that powers many websites, including Wikipedia. The Citizen skin, which incorporates extensions to enhance user experience, has an XSS vulnerability that allows a threat actor to compromise system integrity and potentially leak sensitive data. This vulnerability affects versions 1.9.4 to before 3.4.0 and is particularly alarming due to the potential widespread impact on platforms using the susceptible Citizen skin.
Vulnerability Summary
CVE ID: CVE-2025-53368
Severity: Critical, CVSS Score: 8.6
Attack Vector: Web-based
Privileges Required: Low (page editing privileges)
User Interaction: Required (searching for specific pages)
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
MediaWiki Citizen Skin | 1.9.4 to before 3.4.0
How the Exploit Works
The root cause of the vulnerability lies in the lack of proper sanitization of page descriptions by the Citizen skin when using the old search bar. In this scenario, any user with page editing privileges can craft malicious JavaScript payloads, which are subsequently inserted as raw HTML into the Document Object Model (DOM). When another user searches for the tampered page, the harmful script executes, leading to a cross-site scripting (XSS) attack. This can result in a range of malicious activities, from stealing session cookies to injecting harmful content, which can compromise the system and potentially lead to data leakage.
Conceptual Example Code
Let’s consider a conceptual example of how this exploit might manifest. An attacker with page-editing privileges could insert a malicious script into the page description like so:
<p>This is a page description. <img src='x' onerror='stealCookies()'></p>In this hypothetical example, `stealCookies()` is a function designed by the attacker to steal user session cookies when the malformed image fails to load, triggering the `onerror` event. When another user searches and lands on this page, the malicious script executes, compromising the user’s session.
Mitigation and Prevention
The creators of the Citizen skin have addressed this vulnerability in version 3.4.0. All users are strongly advised to update to the latest version to avoid potential exploitation. Alternatively, deploying a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can provide temporary mitigation by detecting and blocking suspicious payloads.