SQL injection vulnerability in the PostgreSQL auth module for courier 0.40 and earlier allows remote attackers to execute SQL code via the user name.
Courier sqwebmail before 0.40.0 does not quickly drop privileges after startup in certain cases, which could allow local users to read arbitrary files.
libs/comverp.c in Courier MTA before 0.53.2 allows attackers to cause a denial of service (CPU consumption) via unknown vectors involving usernames that contain the "=" (equals) character, which is not properly handled during encoding.