CVE-2025-64209 identifies a missing authorization vulnerability in the StylemixThemes Masterstudy WordPress plugin, affecting all versions prior to 4.8.122. The flaw arises because certain functionality within the plugin is not properly constrained by Access Control Lists (ACLs), allowing unauthenticated remote attackers to invoke functions or access data that should be restricted. The vulnerability does not require any privileges or user interaction, making it remotely exploitable over the network. The CVSS 3.1 base score of 7.5 reflects a high severity primarily due to the impact on confidentiality, as attackers can access sensitive information without authentication. The vulnerability does not affect integrity or availability directly. No known public exploits or active exploitation have been reported yet, but the nature of the flaw makes it a significant risk for sites using the Masterstudy plugin, especially those exposing educational content or user data. The lack of patch links indicates that a fix may not yet be publicly available, emphasizing the need for vigilance and interim mitigations. The vulnerability was reserved in late October 2025 and published in mid-December 2025, indicating recent discovery and disclosure. Organizations relying on Masterstudy for e-learning platforms should assess exposure and implement compensating controls until an official patch is released.

For European organizations, the missing authorization vulnerability in Masterstudy could lead to unauthorized disclosure of sensitive educational content, user information, or administrative data. This can undermine user privacy, violate data protection regulations such as GDPR, and damage organizational reputation. Educational institutions and e-learning providers using Masterstudy are particularly vulnerable, as attackers could harvest confidential student data or course materials. The ease of exploitation without authentication increases the risk of automated scanning and mass exploitation attempts. While the vulnerability does not directly affect system integrity or availability, the confidentiality breach alone can have severe compliance and operational consequences. Additionally, attackers gaining access to restricted functionality might leverage this foothold for further attacks or lateral movement within the affected environment. The impact is heightened in countries with large e-learning markets and widespread WordPress adoption, where Masterstudy is more commonly deployed.

1. Monitor StylemixThemes official channels for the release of a security patch addressing CVE-2025-64209 and apply updates immediately upon availability. 2. Until a patch is released, implement web application firewall (WAF) rules to restrict access to Masterstudy plugin endpoints that are not intended for public use, based on URL patterns and request behaviors. 3. Conduct a thorough access control audit of the Masterstudy plugin configuration and WordPress user roles to ensure minimal privileges and disable any unnecessary features. 4. Employ network segmentation to isolate the WordPress environment hosting Masterstudy from sensitive internal systems. 5. Enable detailed logging and monitoring for unusual access patterns or attempts to invoke restricted functionality within the plugin. 6. Consider temporarily disabling the Masterstudy plugin if the risk outweighs operational needs and no immediate patch is available. 7. Educate administrators about the vulnerability and encourage prompt incident response readiness in case of exploitation attempts.