The WPCOM Member plugin for WordPress is vulnerable to authentication bypass via brute force in all versions up to, and including, 1.7.16. This is due to weak OTP (One-Time Password) generation using only 6 numeric digits combined with a 10-minute validity window and no rate limiting on verification attempts. This makes it possible for unauthenticated attackers to brute-force the verification code and authenticate as any user, including administrators, if they know the target's phone number, and