Unspecified vulnerability in Cisco IOS 12.2SXA, SXB, SXD, and SXF; and the MSFC2, MSFC2a and MSFC3 running in Hybrid Mode on Cisco Catalyst 6000, 6500 and Cisco 7600 series systems; allows remote attackers on a local network segment to cause a denial of service (software reload) via a certain MPLS packet.