Executive brief
A vulnerability in the Really Simple Security plugin for WordPress allows attackers to bypass two-factor authentication (2FA). If an attacker has already obtained a user's password through other means, they can log in to the website without needing the required email security code. This could lead to unauthorized access to sensitive administrative areas and user accounts, potentially compromising the entire website.
Technical details
The vulnerability exists within the REST API implementation of the Really Simple Security plugin (formerly Really Simple SSL). Specifically, the 'do_not_ask_again' and 'skip_onboarding' endpoints under the '/wp-json/really-simple-security/v1/two-fa/v2/' namespace do not properly validate that a second-factor challenge has been completed before issuing an authentication cookie. An attacker who has already obtained a user's primary credentials can capture a 'login_nonce' from the standard login page and replay it against these vulnerable endpoints. This results in a successful WordPress authentication session, effectively bypassing the email-based One-Time Password (OTP) protection. The issue is resolved in version 9.5.10.1.
Affected products
- Really Simple Plugins Really Simple Security (formerly Really Simple SSL) < 9.5.10.1
Timeline
- 2026-05-12: disclosed: Initial public disclosure by researcher
- 2026-06-02: advisory: NVD publication date