Cisco Security Advisory – Cisco IOS and Cisco IOS XR contain a vulnerability when processing specially crafted IPv6 packets with a Type 0 Routing Header present. Exploitation of this vulnerability can lead to information leakage on affected IOS and IOS XR devices, and may also result in a crash of the affected IOS device. Successful exploitation on an affected device running Cisco IOS XR will not result in a crash of the device itself, but may result in a crash of the IPv6 subsystem.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/58383/cisco-sa-20070808-IOS-IPv6-leak.txt
Source: https://packetstormsecurity.com/files/58383/Cisco-Security-Advisory-20070808-IOS-IPv6-leak.html