Yahoo Messenger 5.x-6.0 - Denial of Service via Malformed Room Request Packet
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.