CVE-2025-4963 in WP Extended Plugin
Summary
by MITRE • 05/28/2025
The WP Extended plugin for WordPress is vulnerable to Stored Cross-Site Scripting via SVG File uploads in all versions up to, and including, 3.0.15 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Author-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses the SVG file.
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Analysis
by VulDB Data Team • 05/28/2025
The vulnerability identified as CVE-2025-4963 affects the WP Extended plugin for WordPress, representing a critical stored cross-site scripting vulnerability that compromises the security of web applications. This issue exists in all versions up to and including 3.0.15, making it a widespread concern for WordPress users who rely on this plugin for extended functionality. The vulnerability stems from inadequate input sanitization and output escaping mechanisms within the plugin's SVG file upload handling process, creating a persistent security weakness that can be exploited by malicious actors with relatively low privileges.
The technical flaw manifests when authenticated attackers with Author-level access or higher upload malicious SVG files to the WordPress system. These SVG files contain embedded malicious scripts that are stored within the application's database and subsequently executed whenever legitimate users access the SVG files through the web interface. This represents a classic stored XSS vulnerability pattern where malicious code persists in the system and executes automatically during normal user interactions. The vulnerability operates at the intersection of file upload security and cross-site scripting defenses, where the plugin fails to properly validate and sanitize SVG content before storing it in the database. The insufficient output escaping means that even if input validation were somehow effective, the stored malicious content would still execute when rendered in web browsers.
The operational impact of this vulnerability is significant for WordPress installations using the affected plugin, as it allows attackers to execute arbitrary web scripts in the context of any user who accesses the compromised SVG files. This creates a persistent threat vector that can be used to steal user sessions, redirect visitors to malicious sites, deface websites, or harvest sensitive information from authenticated users. The vulnerability is particularly concerning because it requires only Author-level privileges to exploit, which is often accessible to users who can create and edit content on WordPress sites. This means that malicious actors with moderate access rights can compromise the entire site's security, potentially affecting all users who might encounter the malicious SVG files. The stored nature of the vulnerability means that the attack remains effective even after the initial exploit, creating a long-term security risk that can persist until the vulnerability is patched.
Mitigation strategies for CVE-2025-4963 should prioritize immediate patching of the WP Extended plugin to the latest version that addresses this vulnerability. Organizations should also implement additional security measures such as restricting file upload capabilities for users with Author-level access or higher, implementing more robust input validation for SVG files, and employing web application firewalls that can detect and block malicious script injection attempts. The vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and it maps to ATT&CK technique T1566.001 related to spearphishing attachments, as attackers could potentially use this vulnerability to deliver malicious payloads through SVG file uploads. Regular security audits of plugin installations and monitoring for unusual file upload activities should be implemented to detect potential exploitation attempts. System administrators should also consider implementing Content Security Policy headers to provide additional protection against script execution, and maintain regular backups to ensure rapid recovery in case of successful exploitation attempts.