Buffer overflows in Yahoo! Messenger 5,0,0,1064 and earlier allows remote attackers to execute arbitrary code via a ymsgr URI with long arguments to (1) call, (2) sendim, (3) getimv, (4) chat, (5) addview, or (6) addfriend.
Buffer overflow in Yahoo! Messenger 5.0 allows remote attackers to cause a denial of service and possibly execute arbitrary code via a long (1) message or (2) IMvironment field.
Yahoo! Messenger 5.0 allows remote attackers to spoof other users by modifying the username and using the spoofed username for social engineering or denial of service (flooding) attacks.