Cisco IOS before 15.0(1)XA does not properly handle IRC traffic during a specific time period after an initial reload, which allows remote attackers to cause a denial of service (device reload) via an attempted connection to a certain IRC server, related to a "corrupted magic value," aka Bug ID CSCso05336.
The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in Cisco IOS before 15.0(1)XA5 allows remote attackers to cause a denial of service (CPU consumption and device hang) by sending many Router Advertisement (RA) messages with different source addresses, as demonstrated by the flood_router6 program in the thc-ipv6 package, aka Bug ID CSCti33534.
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 12.2 through 12.4, when certain PMTUD, SNAT, or window-size configurations are used, allows remote attackers to cause a denial of service (infinite loop, and device reload or hang) via a TCP segment with crafted options, aka Bug ID CSCsz75186.
Cisco IOS 12.1 through 12.4, and 15.0M before 15.0(1)M1, allows remote attackers to cause a denial of service (interface queue wedge) via malformed H.323 packets, aka Bug ID CSCta19962.
Cisco IOS 12.1 through 12.4, when Cisco Unified Communications Manager Express (CME) or Cisco Unified Survivable Remote Site Telephony (SRST) is enabled, allows remote attackers to cause a denial of service (device reload) via a malformed Skinny Client Control Protocol (SCCP) message, aka Bug ID CSCsz48614, the "SCCP Packet Processing Denial of Service Vulnerability."
Cisco IOS 12.1 through 12.4, when Cisco Unified Communications Manager Express (CME) or Cisco Unified Survivable Remote Site Telephony (SRST) is enabled, allows remote attackers to cause a denial of service (device reload) via a malformed Skinny Client Control Protocol (SCCP) message, aka Bug ID CSCsz49741, the "SCCP Request Handling Denial of Service Vulnerability."
Unspecified vulnerability in Cisco IOS 12.2 through 12.4 allows remote attackers to cause a denial of service (device reload) via a crafted H.323 packet, aka Bug ID CSCsz38104.
Cisco IOS 12.0 through 12.4, when IP-based tunnels and the Cisco Express Forwarding feature are enabled, allows remote attackers to cause a denial of service (device reload) via a malformed packet that is not properly handled during switching from one tunnel to a second tunnel, aka Bug IDs CSCsh97579 and CSCsq31776.
Cisco IOS 12.0 through 12.4, when IP-based tunnels and the Cisco Express Forwarding feature are enabled, allows remote attackers to cause a denial of service (device reload) via malformed packets, aka Bug ID CSCsx70889.