A vulnerability in the Cisco Cluster Management Protocol (CMP) processing code in Cisco IOS and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a reload of an affected device or remotely execute code with elevated privileges. The Cluster Management Protocol utilizes Telnet internally as a signaling and command protocol between cluster members. The vulnerability is due to the combination of two factors: (1) the failure to restrict the use of CMP-specific Telnet options only to internal, local communications between cluster members and instead accept and process such options over any Telnet connection to an affected device; and (2) the incorrect processing of malformed CMP-specific Telnet options. An attacker could exploit this vulnerability by sending malformed CMP-specific Telnet options while establishing a Telnet session with an affected Cisco device configured to accept Telnet connections. An exploit could allow an attacker to execute arbitrary code and obtain full control of the device or cause a reload of the affected device. This affects Catalyst switches, Embedded Service 2020 switches, Enhanced Layer 2 EtherSwitch Service Module, Enhanced Layer 2/3 EtherSwitch Service Module, Gigabit Ethernet Switch Module (CGESM) for HP, IE Industrial Ethernet switches, ME 4924-10GE switch, RF Gateway 10, and SM-X Layer 2/3 EtherSwitch Service Module. Cisco Bug IDs: CSCvd48893.

Multiple Cisco networking products allow remote attackers to cause a denial of service on the local network via a series of ARP packets sent to the router's interface that contains a different MAC address for the router, which eventually causes the router to overwrite the MAC address in its ARP table.

Unspecified Cisco Catalyst Switches allow remote attackers to cause a denial of service (device crash) via an IP packet with the same source and destination IPs and ports, and with the SYN flag set (aka LanD). NOTE: the provenance of this issue is unknown; the details are obtained solely from the BID.

The HTTP server in Cisco IOS on Catalyst switches does not properly handle TCP socket events, which allows remote attackers to cause a denial of service (device crash) via crafted packets on TCP port (1) 80 or (2) 443, aka Bug ID CSCuc53853.