Cisco IOS 12.2(15) and earlier allows remote attackers to cause a denial of service (refused VTY (virtual terminal) connections), via a crafted TCP connection to the Telnet or reverse Telnet port.
Cisco IOS 11.1(x) through 11.3(x) and 12.0(x) through 12.2(x), when configured for BGP routing, allows remote attackers to cause a denial of service (device reload) via malformed BGP (1) OPEN or (2) UPDATE messages.
Buffer overflow in the HTTP server for Cisco IOS 12.2 and earlier allows remote attackers to execute arbitrary code via an extremely long (2GB) HTTP GET request.
Cisco IOS 11.x and 12.0 through 12.2 allows remote attackers to cause a denial of service (traffic block) by sending a particular sequence of IPv4 packets to an interface on the device, causing the input queue on that interface to be marked as full.
Buffer overflow in Cisco IOS 11.2.x to 12.0.x allows remote attackers to cause a denial of service and possibly execute commands via a large number of OSPF neighbor announcements.
Cisco IOS 11.1 through 12.2, when HSRP support is not enabled, allows remote attackers to cause a denial of service (CPU consumption) via randomly sized UDP packets to the Hot Standby Routing Protocol (HSRP) port 1985.
Cisco IOS 11.2.x and 12.0.x does not limit the size of its redirect table, which allows remote attackers to cause a denial of service (memory consumption) via spoofed ICMP redirect packets to the router.
Heap-based buffer overflow in the TFTP server capability in Cisco IOS 11.1, 11.2, and 11.3 allows remote attackers to cause a denial of service (reset) or modify configuration via a long filename.
Cisco IOS 12.2 and earlier running Cisco Discovery Protocol (CDP) allows remote attackers to cause a denial of service (memory consumption) via a flood of CDP neighbor announcements.
Cisco devices IOS 12.0 and earlier allow a remote attacker to cause a crash, or bad route updates, via malformed BGP updates with unrecognized transitive attribute.