Cisco IOS 12.0 through 12.4 and IOS XR before 3.2, with IPv6 enabled, allows remote attackers on a local network segment to cause a denial of service (device reload) and possibly execute arbitrary code via a crafted IPv6 packet.
Cisco IOS 12.0 through 12.3YL, with BGP enabled and running the bgp log-neighbor-changes command, allows remote attackers to cause a denial of service (device reload) via a malformed BGP packet.
Secure Shell (SSH) 2 in Cisco IOS 12.0 through 12.3 allows remote attackers to cause a denial of service (device reload) (1) via a username that contains a domain name when using a TACACS+ server to authenticate, (2) when a new SSH session is in the login phase and a currently logged in user issues a send command, or (3) when IOS is logging messages and an SSH session is terminated while the server is sending data.
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 VACM (View-based Access Control MIB) for Catalyst Operating Software (CatOS) 5.5 and 6.1 and IOS 12.0 and 12.1 allows remote attackers to read and modify device configuration via the read-write community string.
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.
Cisco IOS 12.0 through 12.2, when IP routing is disabled, accepts false ICMP redirect messages, which allows remote attackers to cause a denial of service (network routing modification).
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.