Cisco routers and switches running IOS 12.0 through 12.2.1 allows a remote attacker to cause a denial of service via a flood of UDP packets.

HTTP server for Cisco IOS 11.3 to 12.2 allows attackers to bypass authentication and execute arbitrary commands, when local authorization is being used, by specifying a high access level in the URL.

Cisco IOS 12.0(5)XU through 12.1(2) allows remote attackers to read system administration and topology information via an "snmp-server host" command, which creates a readable "community" community string if one has not been previously created.

The HTTP server in Cisco IOS 12.0 through 12.1 allows local users to cause a denial of service (crash and reload) via a URL containing a "?/" string.

Cisco Gigabit Switch Routers (GSR) with Fast Ethernet / Gigabit Ethernet cards, from IOS versions 11.2(15)GS1A up to 11.2(19)GS0.2 and some versions of 12.0, do not properly handle line card failures, which allows remote attackers to bypass ACLs or force the interface to stop forwarding packets.

The on-line help system options in Cisco routers allows non-privileged users without "enabled" access to obtain sensitive information via the show command.

The IOS HTTP service in Cisco routers and switches running IOS 11.1 through 12.1 allows remote attackers to cause a denial of service by requesting a URL that contains a %% string.

Cisco IOS 11.x and 12.x allows remote attackers to cause a denial of service by sending the ENVIRON option to the Telnet daemon before it is ready to accept it, which causes the system to reboot.

In Cisco routers under some versions of IOS 12.0 running NAT, some packets may not be filtered by input access list filters.

Cisco IOS 12.0 and other versions can be crashed by malicious UDP packets to the syslog port.