CVE-2023-4823 is a stored Cross-Site Scripting (XSS) vulnerability affecting the WordPress plugin "WP Meta and Date Remover" in versions prior to 2.2.0. This plugin provides an AJAX endpoint intended for configuring plugin settings. However, this endpoint lacks proper capability checks, meaning it does not verify whether the user has sufficient privileges to perform configuration changes. Furthermore, the user input submitted through this endpoint is not sanitized or escaped before being stored and later output on the website. As a result, any authenticated user, including low-privileged roles such as subscribers, can inject malicious JavaScript code that will be persistently stored and executed in the context of other users viewing the affected pages. The vulnerability is categorized under CWE-79 (Cross-Site Scripting), which allows attackers to execute arbitrary scripts in victims' browsers, potentially leading to session hijacking, privilege escalation, defacement, or distribution of malware. The CVSS v3.1 base score is 5.4 (medium severity), with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L), user interaction (UI:R), scope changed (S:C), and low impact on confidentiality and integrity (C:L, I:L), with no impact on availability (A:N). No known exploits in the wild have been reported yet. The vulnerability arises from the combination of missing authorization checks and lack of input sanitization on an AJAX endpoint, which is accessible to any authenticated user, making it a significant risk for WordPress sites using this plugin.

For European organizations using the WP Meta and Date Remover plugin, this vulnerability poses a risk of persistent XSS attacks that can compromise the confidentiality and integrity of user sessions and data. Attackers with subscriber-level access could inject malicious scripts that execute in the browsers of administrators or other users with higher privileges, potentially leading to session hijacking, unauthorized actions, or distribution of malware within the organization’s WordPress environment. This could result in data breaches, defacement of websites, loss of customer trust, and regulatory compliance issues under GDPR due to unauthorized access or data leakage. Since WordPress is widely used across Europe for corporate websites, blogs, and e-commerce platforms, exploitation could disrupt business operations and damage brand reputation. The scope of impact is limited to organizations that have installed this specific plugin and have not updated it to a patched version. However, the ease of exploitation by low-privileged authenticated users increases the risk, especially in environments with many registered users or weak user management policies.

1. Immediate update: Organizations should upgrade the WP Meta and Date Remover plugin to version 2.2.0 or later, where this vulnerability is fixed. 2. Access control review: Restrict user roles and permissions to minimize the number of authenticated users who can access plugin configuration endpoints. Consider removing or disabling subscriber-level accounts if not necessary. 3. Input validation and sanitization: If custom modifications or similar plugins are used, ensure all user inputs are properly sanitized and escaped before storage and output. 4. Web application firewall (WAF): Deploy a WAF with rules to detect and block common XSS payloads targeting AJAX endpoints. 5. Monitoring and logging: Enable detailed logging of AJAX requests and monitor for unusual activity or attempts to inject scripts. 6. Security awareness: Educate site administrators and users about the risks of XSS and the importance of applying updates promptly. 7. Plugin audit: Regularly audit installed plugins for vulnerabilities and remove unused or unmaintained plugins to reduce attack surface.