CVE-2025-46520 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the 'Related Posts via Taxonomies' plugin developed by alphasis, affecting versions up to 1.0.1. The vulnerability allows an attacker to perform unauthorized actions on behalf of an authenticated user by exploiting the lack of proper CSRF protections. Specifically, this vulnerability can lead to Stored Cross-Site Scripting (XSS) attacks, where malicious scripts are injected and persistently stored within the application. When a victim user accesses the compromised content, the malicious script executes in their browser context, potentially leading to session hijacking, credential theft, or further exploitation of the victim's privileges. The vulnerability arises due to insufficient validation of requests modifying taxonomy-related data, allowing attackers to craft malicious requests that are executed without user consent. Although no known exploits are currently reported in the wild, the presence of stored XSS combined with CSRF significantly increases the attack surface, as it does not require direct user interaction beyond visiting a compromised page. The plugin is commonly used in content management systems to display related posts based on taxonomies, making it a target for attackers aiming to compromise website integrity and user trust. No official patches or updates have been released at the time of this report, highlighting the need for immediate mitigation steps.

For European organizations, the impact of this vulnerability can be substantial, especially for those relying on the 'Related Posts via Taxonomies' plugin within their web infrastructure. Exploitation could lead to unauthorized actions performed under the guise of legitimate users, including administrators or content editors, resulting in unauthorized content modification, defacement, or insertion of malicious scripts. Stored XSS can compromise the confidentiality of user data by stealing session cookies or credentials, potentially leading to broader network access or data breaches. The integrity of web content can be undermined, damaging organizational reputation and user trust. Availability may also be affected if attackers leverage the vulnerability to inject disruptive scripts or conduct further attacks such as phishing or malware distribution. Given the widespread use of content management systems in European public and private sectors, including media, education, and e-commerce, the vulnerability poses a risk to critical digital services. Additionally, compliance with the EU General Data Protection Regulation (GDPR) could be jeopardized if personal data is exposed or mishandled due to exploitation, leading to legal and financial repercussions.

1. Immediate mitigation should include disabling or uninstalling the 'Related Posts via Taxonomies' plugin until a security patch is released. 2. Implement Web Application Firewall (WAF) rules to detect and block suspicious CSRF and XSS payloads targeting taxonomy-related endpoints. 3. Enforce strict Content Security Policy (CSP) headers to limit the execution of unauthorized scripts within the web application. 4. Conduct thorough input validation and sanitization on all taxonomy-related inputs to prevent injection of malicious code. 5. Require authentication and implement anti-CSRF tokens for all state-changing requests within the plugin's scope. 6. Monitor web server logs and application behavior for unusual requests or anomalies indicative of exploitation attempts. 7. Educate administrators and content editors about the risks of CSRF and XSS, emphasizing cautious handling of links and content. 8. Plan for timely application of official patches once available and maintain an inventory of all plugins and their versions to facilitate rapid response. 9. Consider isolating the plugin's functionality or migrating to alternative solutions with robust security track records.