CVE-2025-53491 in FlaggedRevs Extension
Summary
by MITRE • 07/07/2025
Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation Mediawiki - FlaggedRevs Extension allows Cross-Site Scripting (XSS).This issue affects Mediawiki - FlaggedRevs Extension: from 1.43.X before 1.43.2.
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Analysis
by VulDB Data Team • 07/07/2025
The vulnerability CVE-2025-53491 represents a critical improper neutralization of input during web page generation, specifically manifesting as a cross-site scripting flaw within the Wikimedia Foundation MediaWiki FlaggedRevs extension. This weakness allows malicious actors to inject arbitrary web scripts into web pages viewed by other users, creating a significant security risk for wiki communities that rely on this extension for content review processes. The vulnerability exists in MediaWiki versions from 1.43.0 through 1.43.1, making these releases particularly susceptible to exploitation by threat actors seeking to compromise user sessions or manipulate content presentation.
The technical flaw stems from insufficient input validation and output escaping mechanisms within the FlaggedRevs extension's handling of user-supplied data during page generation processes. When users submit content or interact with flagged revision features, the extension fails to properly sanitize or escape special characters that could be interpreted as HTML or JavaScript code by web browsers. This improper neutralization creates an environment where attackers can craft malicious payloads that execute in the context of other users' browsers, potentially leading to session hijacking, data exfiltration, or unauthorized actions performed on behalf of victims. The vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws resulting from inadequate input sanitization and output escaping.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to manipulate the integrity of wiki content and compromise user trust within collaborative environments. In the context of MediaWiki's FlaggedRevs extension, which is designed to manage content review and approval workflows, an attacker could potentially inject malicious scripts into revision histories or flagged content displays, affecting the reliability of the review process. This creates a cascading effect where legitimate users may be exposed to malicious code execution when viewing content that has been flagged for review, particularly in environments where multiple editors collaborate on sensitive information.
Organizations and users affected by this vulnerability should immediately implement mitigations including upgrading to MediaWiki version 1.43.2 or later, which contains the necessary patches to address the input neutralization issues. Additionally, administrators should review their current extension configurations and consider implementing additional security measures such as Content Security Policy headers to limit script execution capabilities. The vulnerability demonstrates the importance of proper input validation and output escaping practices in web applications, aligning with ATT&CK technique T1566.001 for initial access through malicious web content and T1059.001 for command and scripting interpreter usage. Regular security audits of web applications and their extensions should be conducted to identify similar input sanitization weaknesses that could lead to similar exploitation vectors.