CVE-2025-0809 in Link Fixer Plugin
Summary
by MITRE • 01/31/2025
The Link Fixer plugin for WordPress is vulnerable to Stored Cross-Site Scripting via broken links in all versions up to, and including, 3.4 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers 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 • 02/06/2025
The vulnerability identified as CVE-2025-0809 affects the Link Fixer plugin for WordPress, a widely used tool designed to identify and correct broken links on websites. This plugin operates by scanning web pages for invalid hyperlinks and providing automated fixes or notifications about problematic URLs. The vulnerability resides in the plugin's handling of broken link data, specifically in how it processes and displays user-provided link information without adequate sanitization measures. The issue impacts all versions of the plugin up to and including version 3.4, making it a significant concern for WordPress administrators who have not yet updated their installations.
The technical flaw stems from insufficient input sanitization and output escaping mechanisms within the plugin's codebase. When the plugin encounters broken links, it stores this information in the WordPress database and later retrieves it for display purposes. However, the plugin fails to properly sanitize the link data before storing it and does not adequately escape the output when rendering the broken link information on web pages. This creates a classic stored cross-site scripting vulnerability where malicious actors can inject arbitrary JavaScript code into the link data that will execute whenever legitimate users view the affected pages. The vulnerability is classified as CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security.
The operational impact of this vulnerability is substantial as it allows unauthenticated attackers to execute malicious scripts in the context of any user who views pages containing the injected content. This means that when administrators or other website visitors access pages that display the broken link information, their browsers will execute the attacker's malicious code. The potential consequences include session hijacking, where attackers can steal user authentication cookies and impersonate legitimate users, data theft from the WordPress site, or even redirection to malicious websites that could distribute malware. The vulnerability is particularly dangerous because it requires no authentication to exploit, making it accessible to anyone who can access the affected WordPress site, and the attack can persist as long as the malicious content remains in the database.
Mitigation strategies for this vulnerability should prioritize immediate plugin updates to the latest version where the XSS flaw has been addressed. WordPress administrators should also implement additional security measures such as content security policies that restrict script execution on the site, regular monitoring of the plugin's database entries for suspicious content, and implementing web application firewalls that can detect and block malicious script injection attempts. The ATT&CK framework categorizes this vulnerability under T1566 - Phishing, as attackers can leverage the stored XSS to redirect users to malicious sites or steal session information. Additionally, implementing proper input validation and output escaping practices as recommended by the OWASP Top Ten project would help prevent similar vulnerabilities in the future. Organizations should also consider performing regular security audits of their WordPress plugins and maintaining up-to-date vulnerability management processes to identify and remediate such issues before they can be exploited in the wild.