The miniOrange OTP Login, Verification and SMS Notifications plugin for WordPress is vulnerable to Authentication Bypass leading to Administrator Account Takeover in all versions up to, and including, 5.5.1. This is due to the `um_reset_password_process_hook()` function performing no server-side verification that the OTP validation step was completed, and relying solely on a public `form_nonce` nonce that the plugin itself emits to unauthenticated visitors via the `moumprvar` JavaScript object on the Ultimate Member password reset page, while still accepting the attacker-controlled `username_b` parameter to target any WordPress user without role restriction or any binding to a previously validated OTP session. This makes it possible for unauthenticated attackers to obtain a freshly generated password-reset URL for an arbitrary Administrator account — returned in a 302 `Location` header — and use it to take full control of that account. Exploitation requires the Ultimate Member Password Reset Form integration to be active and the plugin to not be configured for phone-only reset.

Quoted source text, attributed separately from HOL analysis.

The miniOrange OTP Login, Verification and SMS Notifications plugin for WordPress is vulnerable to Authentication Bypass leading to Administrator Account Takeover in all versions up to, and including, 5.5.1. This is due to the `um_reset_password_process_hook()` function performing no server-side verification that the OTP validation step was completed, and relying solely on a public `form_nonce` nonce that the plugin itself emits to unauthenticated visitors via the `moumprvar` JavaScript object on the Ultimate Member password reset page, while still accepting the attacker-controlled `username_b` parameter to target any WordPress user without role restriction or any binding to a previously validated OTP session. This makes it possible for unauthenticated attackers to obtain a freshly generated password-reset URL for an arbitrary Administrator account — returned in a 302 `Location` header — and use it to take full control of that account. Exploitation requires the Ultimate Member Password Reset Form integration to be active and the plugin to not be configured for phone-only reset.

Quoted source text, attributed separately from HOL analysis.