Cisco Security Advisory – Cisco IOS Software is affected by a denial of service vulnerability that may allow a remote unauthenticated attacker to cause an affected device to reload or hang. The vulnerability may be triggered by a TCP segment containing crafted TCP options that is received during the TCP session establishment phase. In addition to specific, crafted TCP options, the device must have a special configuration to be affected by this vulnerability. Cisco has released free software updates that address this vulnerability.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/87604/cisco-sa-20100324-tcp.txt
Source: https://packetstormsecurity.com/files/87604/Cisco-Security-Advisory-20100324-tcp.html