twofactor_gauthenticator vulnerabilities

The twofactor_gauthenticator plugin for Roundcube is vulnerable to 2FA authentication bypass by spoofed client address headers. Due to the lack of validation of the Client-IP and X-Forwarded-For headers, an attacker who obtains the user's password can spoof a whitelisted IP address and bypass the second factor.

The twofactor_gauthenticator plugin for Roundcube is vulnerable to session persistence after failed 2FA verification. Due to the lack of server-side session destruction, an attacker can ignore the logout redirect and keep the session alive.

The twofactor_gauthenticator plugin for Roundcube is vulnerable to brute-forcing of the second-factor code. Due to the lack of rate limiting, an attacker who obtains the user's password can submit arbitrary 6-digit codes, resulting in second-factor bypass and unauthorized access.