aMSN 0.90 for Microsoft Windows allows local users to obtain sensitive information such as hashed passwords from (1) hotlog.htm and (2) config.xml.

aMSN (aka Alvaro's Messenger) allows remote attackers to cause a denial of service (client hang and termination of client's instant-messaging session) by repeatedly sending crafted data to the default file-transfer port (TCP 6891).

login_screen.tcl in aMSN (aka Alvaro's Messenger) before 0.97.1 saves a password after logout, which allows physically proximate attackers to hijack a session by visiting an unattended workstation.