CVE-2025-2889 in Link Library Plugin
Summary
by MITRE • 04/05/2025
The Link Library plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Link Additional Parameters in all versions up to, and including, 7.7.3 due to insufficient input sanitization and output escaping. This makes it possible for authenticated attackers, with Contributor-level access and above, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 04/05/2025
The vulnerability identified as CVE-2025-2889 affects the Link Library plugin for WordPress, a widely used tool for managing and displaying links within WordPress environments. This issue represents a critical security flaw that has been present in all versions up to and including 7.7.3, creating a persistent risk for WordPress installations that rely on this plugin for link management functionality. The vulnerability specifically targets the plugin's handling of Link Additional Parameters, which are used to extend the functionality of links within the WordPress ecosystem. The flaw stems from inadequate input sanitization processes and insufficient output escaping mechanisms that fail to properly validate and sanitize user-supplied data before it is stored and subsequently rendered in web pages.
The technical exploitation of this vulnerability occurs through a stored cross-site scripting attack vector that requires authenticated access with Contributor-level privileges or higher. This means that attackers who have gained access to a WordPress account with at least Contributor permissions can leverage this flaw to inject malicious scripts into the plugin's parameter handling system. When legitimate users subsequently access pages containing these maliciously injected parameters, the stored scripts execute in their browsers, potentially leading to session hijacking, data theft, or further compromise of the affected WordPress installation. The vulnerability demonstrates a classic failure in the principle of least privilege and input validation, where user-supplied data flows directly from input through storage to output without proper sanitization.
The operational impact of this vulnerability extends beyond simple script execution, as it creates a persistent backdoor within WordPress installations that can be exploited repeatedly by authenticated attackers. Contributors and above typically have significant access within WordPress environments, including the ability to create and modify content, which makes this vulnerability particularly dangerous when considering the potential for privilege escalation or lateral movement within compromised systems. The stored nature of the XSS attack means that the malicious scripts remain active until manually removed from the plugin's parameter storage, providing attackers with sustained access to target systems. This vulnerability directly aligns with CWE-79 which describes cross-site scripting flaws, and represents a clear violation of secure coding practices that should prevent such injection attacks through proper input validation and output encoding.
Organizations affected by this vulnerability should immediately implement mitigation strategies that include updating to the latest version of the Link Library plugin where available, implementing additional input validation measures, and monitoring for suspicious activity in link management areas. The recommended approach involves deploying web application firewalls that can detect and block malicious script injection attempts, implementing stricter access controls to limit Contributor-level privileges where possible, and conducting thorough security audits of all WordPress plugins to identify similar vulnerabilities. This vulnerability also highlights the importance of the principle of defense in depth, where multiple layers of security controls should be implemented to protect against various attack vectors, including those that may exploit similar input validation weaknesses in other components of the WordPress ecosystem. The ATT&CK framework categorizes this type of vulnerability under techniques involving command and control communications and privilege escalation through web application attacks, making it a significant concern for enterprise security teams managing WordPress-based content management systems.