m-FILTER prior to Ver.5.70R01 (Ver.5 Series) and m-FILTER prior to Ver.4.87R04 (Ver.4 Series) allows a remote unauthenticated attacker to bypass authentication and send users' unintended email when email is being sent under the certain conditions. The attacks exploiting this vulnerability have been observed.
NVD-CWE-noinfo, CWE-287