CVE-2025-15370 is an authorization bypass vulnerability identified in the WordPress plugin 'Shield: Blocks Bots, Protects Users, and Prevents Security Breaches' developed by paultgoodchild. The vulnerability stems from an insecure direct object reference (CWE-639) in the MfaGoogleAuthToggle class, where a user-controlled key parameter is not properly validated. This flaw allows any authenticated user with at least Subscriber-level privileges to disable Google Authenticator-based multi-factor authentication (MFA) for any other user on the site. The absence of validation on the key parameter means that attackers can manipulate requests to target arbitrary user accounts, effectively bypassing MFA protections without needing higher privileges or user interaction. The vulnerability affects all plugin versions up to and including 21.0.9. The CVSS v3.1 base score is 4.3 (medium severity), reflecting a network attack vector with low complexity, requiring privileges but no user interaction, and impacting integrity but not confidentiality or availability. Although no public exploits have been reported, the vulnerability poses a significant risk by undermining MFA controls, which are critical for securing WordPress administrative and user accounts. This could lead to easier account takeover if combined with other credential compromise methods. The vulnerability was published on January 16, 2026, and no official patches or updates have been linked yet, necessitating immediate attention from site administrators.

For European organizations, this vulnerability threatens the integrity of user authentication on WordPress sites using the affected plugin. By enabling attackers with minimal privileges to disable MFA for any user, it increases the risk of account compromise, especially for administrative or privileged accounts. This can lead to unauthorized access, data manipulation, or further lateral movement within the affected web infrastructure. Organizations relying on WordPress for critical services, customer portals, or internal tools may face increased exposure to targeted attacks, data breaches, or service disruptions. The impact is particularly concerning for sectors with strict compliance requirements for authentication controls, such as finance, healthcare, and government entities within Europe. Additionally, the ease of exploitation and the widespread use of WordPress in Europe amplify the potential attack surface. Although confidentiality and availability are not directly impacted by this vulnerability, the weakening of MFA protections can facilitate subsequent attacks that compromise these security goals.

European organizations should immediately audit their WordPress installations to identify the presence of the 'Shield: Blocks Bots, Protects Users, and Prevents Security Breaches' plugin and verify the version in use. Until an official patch is released, administrators should consider temporarily disabling the plugin or restricting Subscriber-level user capabilities to prevent exploitation. Implementing strict role-based access controls to limit Subscriber permissions can reduce risk. Monitoring logs for unusual MFA disablement activities or changes to user authentication settings is critical for early detection. Organizations should also enforce additional security layers such as IP whitelisting, Web Application Firewalls (WAFs) with custom rules to detect and block suspicious requests targeting MFA toggling endpoints, and enhanced user behavior analytics. Encouraging users to report unexpected MFA status changes and conducting regular security awareness training can further mitigate risk. Once a patch is available, prompt application is essential. Additionally, consider deploying alternative MFA plugins with robust authorization checks as a contingency.