The Logfile feature in Yahoo! Messenger 5.x through 6.0 can be activated by a YMSGR: URL and writes all output to a single ypager.log file, even when there are multiple users, and does not properly warn later users that the feature has been enabled, which allows local users to obtain sensitive information from other users.

The YMSGR URL handler in Yahoo! Messenger 5.x through 6.0 allows remote attackers to cause a denial of service (disconnect) via a room login or a room join request packet with a third : (colon) and an & (ampersand), which causes Messenger to send a corrupted packet to the server, which triggers a disconnect from the server.

Buffer overflow in Yahoo! Messenger allows remote attackers to execute arbitrary code via the offline mode.

The Audio Setup Wizard (asw.dll) in Yahoo! Messenger 6.0.0.1750, and possibly other versions, allows attackers to arbitrary code by placing a malicious ping.exe program into the Messenger program directory, which is installed with weak default permissions.

Yahoo! Messenger 6.0.0.1750, and possibly other versions before 6.0.0.1921, does not properly display long filenames in file dialog boxes, which could allow remote attackers to trick users into downloading and executing programs via file names containing a large number of spaces and multiple file extensions.

Buffer overflow in Yahoo Instant Messenger 5.6.0.1351 and earlier allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long filename in the download feature.

Buffer overflow in Yahoo! Messenger 5.6 allows remote attackers to cause a denial of service (crash) via a file send request (sendfile) with a large number of "%" (percent) characters after the Yahoo ID.

Buffer overflow in the Yahoo! Audio Conferencing (aka Voice Chat) ActiveX control before 1,0,0,45 allows remote attackers to cause a denial of service and possibly execute arbitrary code via a URL with a long hostname to Yahoo! Messenger or Yahoo! Chat.

Buffer overflow in Yahoo! Messenger before February 2002 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a long set_buddygrp field.

Yahoo! Messenger before February 2002 allows remote attackers to add arbitrary users to another user's buddy list and possibly obtain sensitive information.