Cisco IOS 12.0S through 12.3YH allows remote attackers to cause a denial of service (device restart) via a crafted IPv6 packet.
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A5813
https://exchange.xforce.ibmcloud.com/vulnerabilities/19072
http://www.us-cert.gov/cas/techalerts/TA05-026A.html
http://www.kb.cert.org/vuls/id/472582
http://www.cisco.com/warp/public/707/cisco-sa-20050126-ipv6.shtml