Cisco IOS 12.0

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

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.

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.

Cisco IOS 11.x and 12.0 with ATM support allows attackers to cause a denial of service via the undocumented Interim Local Management Interface (ILMI) SNMP community string.

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.

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.

The Neighbor Discovery (ND) protocol implementation in Cisco IOS on unspecified switches allows remote attackers to bypass the Router Advertisement Guarding functionality via a fragmented IPv6 packet in which the Router Advertisement (RA) message is contained in the second fragment, as demonstrated by (1) a packet in which the first fragment contains a long Destination Options extension header or (2) a packet in which the first fragment contains an ICMPv6 Echo Request message.

The MallocLite implementation in Cisco IOS 12.0, 12.2, 15.0, 15.1, and 15.2 allows remote attackers to cause a denial of service (Route Processor crash) via a BGP UPDATE message with a modified local-preference (aka LOCAL_PREF) attribute length, aka Bug ID CSCtq06538.

Cisco IOS 11.1CC through 12.2 with Cisco Express Forwarding (CEF) enabled includes portions of previous packets in the padding of a MAC level packet when the MAC packet's length is less than the IP level packet length.

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.

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.

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

Cisco PIX firewall and CBAC IP fragmentation attack results in a denial of service.

Multiple cross-site scripting (XSS) vulnerabilities in the HTTP server in Cisco IOS 11.0 through 12.4 allow remote attackers to inject arbitrary web script or HTML via (1) the query string to the ping program or (2) unspecified other aspects of the URI.

Cisco IOS 12.0, 12.1, and 12.2, when GRE IP tunneling is used and the RFC2784 compliance fixes are missing, does not verify the offset field of a GRE packet during decapsulation, which leads to an integer overflow that references data from incorrect memory locations, which allows remote attackers to inject crafted packets into the routing queue, possibly bypassing intended router ACLs.

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