CVE-2025-6595 in MultimediaViewer
Summary
by MITRE • 02/03/2026
Improper Neutralization of Input During Web Page Generation (XSS or 'Cross-site Scripting') vulnerability in Wikimedia Foundation MultimediaViewer.This issue affects MultimediaViewer: from * before 1.39.13, 1.42.7, 1.43.2, 1.44.0.
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Analysis
by VulDB Data Team • 02/04/2026
The CVE-2025-6595 vulnerability represents a critical cross-site scripting flaw within the Wikimedia Foundation MultimediaViewer component, which serves as a media display system for Wikimedia projects including Wikipedia. This vulnerability falls under the CWE-79 category of Cross-Site Scripting and specifically manifests as improper neutralization of input during web page generation processes. The MultimediaViewer component is responsible for rendering multimedia content such as images, videos, and audio files within Wikimedia platforms, making it a prime target for attackers seeking to exploit user sessions or inject malicious content.
The technical flaw stems from insufficient sanitization of user-supplied input parameters that are subsequently incorporated into dynamically generated web pages without proper encoding or validation mechanisms. When users interact with multimedia content through the affected MultimediaViewer, the application fails to adequately escape or filter special characters from input data before rendering it within HTML contexts. This allows attackers to inject malicious scripts that execute within the context of other users' browsers when they view affected media content. The vulnerability specifically impacts versions prior to 1.39.13, 1.42.7, 1.43.2, and 1.44.0, indicating that these release versions contained the necessary input validation and sanitization patches to mitigate the risk.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform session hijacking, steal cookies, redirect users to malicious sites, or even inject additional malware. Given that Wikimedia Foundation operates one of the world's largest collaborative platforms with billions of monthly users, the potential attack surface is enormous. An attacker could exploit this vulnerability to inject malicious code into media galleries, affecting not just individual user sessions but potentially compromising the entire Wikimedia ecosystem. The vulnerability aligns with ATT&CK technique T1531 for 'Modify System Image' and T1059.001 for 'Command and Scripting Interpreter', as it allows for code injection and execution within user contexts.
Mitigation strategies should prioritize immediate deployment of patched versions 1.39.13, 1.42.7, 1.43.2, and 1.44.0 across all Wikimedia Foundation platforms. Organizations should also implement additional defensive measures including Content Security Policy (CSP) headers to restrict script execution, input validation at multiple layers, and regular security audits of web applications. The fix typically involves implementing proper HTML entity encoding for all user-supplied data before insertion into dynamic web content, ensuring that special characters like angle brackets, quotes, and script tags are appropriately escaped. Additionally, organizations should consider implementing Web Application Firewall (WAF) rules to detect and block suspicious input patterns that could indicate XSS attempts, and maintain comprehensive monitoring of user-generated content for potential exploitation attempts.