Unspecified vulnerability in Cisco IOS 12.0 through 12.4, IOS XE 2.1.x through 2.3.x before 2.3.2, and IOS XR 3.2.x through 3.4.3, when Multiprotocol Label Switching (MPLS) and Label Distribution Protocol (LDP) are enabled, allows remote attackers to cause a denial of service (device reload or process restart) via a crafted LDP packet, aka Bug IDs CSCsz45567 and CSCsj25893.

Cisco IOS XR 3.8.1 and earlier allows remote authenticated users to cause a denial of service (process crash) via vectors involving a BGP UPDATE message with many AS numbers prepended to the AS path.

Cisco IOS XR, when configured for Multi Protocol Label Switching (MPLS) and running on Cisco CRS-1 or Cisco 12000 series routers, allows remote attackers to cause a denial of service (Line card crash) via certain MPLS packets, as identified by Cisco bug ID CSCsc77475.

Cisco IOS XR, when configured for Multi Protocol Label Switching (MPLS) and running on Cisco CRS-1 routers, allows remote attackers to cause a denial of service (Modular Services Cards (MSC) crash or "MPLS packet handling problems") via certain MPLS packets, as identified by Cisco bug IDs (1) CSCsd15970 and (2) CSCsd55531.