MRBS before 1.13.0 Password Reset Poisoning via Host Header Injection
MRBS before 1.13.0 contains a password reset poisoning vulnerability that allows unauthenticated attackers to redirect reset links by forging the Host header when $url_base is unset. Attackers can request a reset for a victim so AuthDb::notifyUser() emails a link pointing to their host, capturing the reset key when opened to take over accounts including administrators.