Cisco Security Advisory 20040203 – A layer 2 frame that is encapsulating a layer 3 packet (IP, IPX, etc.) may cause Cisco 6000/6500/7600 series systems with Multilayer Switch Feature Card 2 (MSFC2) that have a FlexWAN or Optical Services Module (OSM) or that run 12.1(8b)E14 to freeze or reset, if the actual length of this frame is inconsistent with the length of the encapsulated layer 3 packet. This vulnerability may be exploited repeatedly causing a denial of service.
You can download this advisory from the following link: https://packetstormsecurity.com/files/download/32614/cisco-sa-20040203-cat6k.txt
Source: https://packetstormsecurity.com/files/32614/Cisco-Security-Advisory-20040203-cat6k.html