Unspecified vulnerability in Cisco IOS 12.2SRE before 12.2(33)SRE4, 15.0, and 15.1, and IOS XE 2.1.x through 3.3.x, when an MPLS domain is configured, allows remote attackers to cause a denial of service (device crash) via a crafted IPv6 packet, related to an expired MPLS TTL, aka Bug ID CSCto07919.
http://www.cisco.com/en/US/products/products_security_advisory09186a0080b95d52.shtml
http://tools.cisco.com/security/center/viewAlert.x?alertId=24125