If a remote user sends a UDP packet to any port in the 22701 - 22705 range to a system running WebTV for Windows, the system may crash entirely or at the least the program will stop responding.
As well, sending a UDP packet to port 22703 specifically has been known to cause automatic reboots.
Microsoft WebTV annclist.exe Malformed UDP Packet Parsing Remote DoS
Remote / Network Access
Denial of Service
Loss of Availability
Patch / RCS
Currently, there are no known workarounds or upgrades to correct this issue. However, Microsoft has released a patch to address this vulnerability. Check the vendor advisory or solution in the references section.