CVE-2025-15403 is a critical security vulnerability classified under CWE-269 (Improper Privilege Management) found in the RegistrationMagic plugin for WordPress, which facilitates custom registration forms, user registration, payment, and login functionalities. The vulnerability exists in all versions up to and including 6.0.7.1. It stems from the 'add_menu' function being accessible through the 'rm_user_exists' AJAX action without proper authentication or authorization checks. This allows an unauthenticated attacker to inject an empty slug into the 'admin_order' parameter, which manipulates the plugin's menu generation logic. When the WordPress admin menu is built, this manipulation causes the plugin to assign the 'manage_options' capability—a powerful administrative privilege—to the targeted user role. Although the initial exploitation vector requires no authentication, further privilege escalation to full administrative control requires the attacker to have at least subscriber-level access. The vulnerability impacts the confidentiality, integrity, and availability of affected WordPress sites by enabling unauthorized administrative access and control. The CVSS v3.1 score of 9.8 reflects the critical nature of this flaw, with attack vector as network (remote), low attack complexity, no privileges required initially, no user interaction needed, and full scope impact. No official patches or updates are currently linked, and no known exploits have been reported in the wild, but the vulnerability's characteristics make it a high-risk target for attackers. Given the popularity of WordPress and the RegistrationMagic plugin, this vulnerability poses a significant threat to websites relying on this plugin for user management and payment processing.

The impact of CVE-2025-15403 is severe for organizations worldwide using the RegistrationMagic plugin. Successful exploitation allows attackers to escalate privileges from unauthenticated or low-privileged users to administrative levels, granting full control over the WordPress site. This can lead to unauthorized access to sensitive data, modification or deletion of content, installation of backdoors or malware, and disruption of website availability. For e-commerce or payment-enabled sites using this plugin, attackers could manipulate transactions or steal payment information, resulting in financial loss and reputational damage. Additionally, compromised administrative access can facilitate lateral movement within the hosting environment, potentially affecting other systems. The ease of exploitation and lack of required user interaction increase the likelihood of automated attacks and widespread exploitation once public exploits emerge. Organizations that do not promptly address this vulnerability risk severe operational, financial, and compliance consequences.

1. Immediate mitigation involves disabling or uninstalling the RegistrationMagic plugin until a security patch is released. 2. Monitor and restrict access to the 'rm_user_exists' AJAX action by implementing web application firewall (WAF) rules that block suspicious requests targeting this endpoint. 3. Limit user roles and permissions strictly, ensuring that subscriber accounts or other low-privileged users cannot be created or manipulated without oversight. 4. Employ WordPress security plugins that can detect and block privilege escalation attempts or anomalous administrative capability assignments. 5. Conduct regular audits of user roles and capabilities to identify unauthorized privilege changes. 6. Keep WordPress core and all plugins updated; once a patch for this vulnerability is released, apply it immediately. 7. Implement network-level protections such as IP whitelisting or rate limiting on AJAX endpoints to reduce exposure. 8. Educate administrators about monitoring logs for unusual AJAX activity or unexpected changes in user privileges. 9. Consider deploying intrusion detection systems (IDS) that can alert on privilege escalation patterns specific to WordPress plugins. These targeted actions go beyond generic advice by focusing on the specific attack vector and plugin behavior.