The Network-Based Application Recognition (NBAR) protocol implementation in Cisco IOS 15.3(100)M and earlier on Cisco 2900 Integrated Services Router (aka Cisco Internet Router) devices allows remote attackers to cause a denial of service (NBAR process hang) via IPv4 packets, aka Bug ID CSCuo73682.
The Ethernet Connectivity Fault Management (CFM) handling feature in Cisco IOS 12.2(33)SRE9a and earlier and IOS XE 3.13S and earlier allows remote attackers to cause a denial of service (device reload) via malformed CFM packets, aka Bug ID CSCuq93406.
The Locator/ID Separation Protocol (LISP) implementation in Cisco IOS 15.3(3)S and earlier and IOS XE does not properly validate parameters in ITR control messages, which allows remote attackers to cause a denial of service (CEF outage and packet drops) via malformed messages, aka Bug ID CSCun73782.
Cisco IOS before 15.3(2)S allows remote attackers to bypass interface ACL restrictions in opportunistic circumstances by sending IPv6 packets in an unspecified scenario in which expected packet drops do not occur for "a small percentage" of the packets, aka Bug ID CSCty73682.
Cisco IOS before 15.3(1)T on Cisco 2900 devices, when a VWIC2-2MFT-T1/E1 card is configured for TDM/HDLC mode, allows remote attackers to cause a denial of service (serial-interface outage) via certain Frame Relay traffic, aka Bug ID CSCub13317.
Cisco IOS before 15.3(2)T, when scansafe is enabled, allows remote attackers to cause a denial of service (latency) via SYN packets that are not accompanied by SYN-ACK packets from the Scan Safe Tower, aka Bug ID CSCub85451.
The ios-authproxy implementation in Cisco IOS before 15.1(1)SY3 allows remote attackers to cause a denial of service (webauth and HTTP service outage) via vectors that trigger incorrectly terminated HTTP sessions, aka Bug ID CSCtz99447.
Cisco IOS before 15.1(2)SY allows remote authenticated users to cause a denial of service (device crash) by establishing an SSH session from a client and then placing this client into a (1) slow or (2) idle state, aka Bug ID CSCto87436.
Cisco IOS before 15.1(1)SY1 allows remote authenticated users to cause a denial of service (device reload) by establishing a VPN session and then sending malformed IKEv2 packets, aka Bug ID CSCub39268.
The Flex-VPN load-balancing feature in the ipsec-ikev2 implementation in Cisco IOS before 15.1(1)SY3 does not require authentication, which allows remote attackers to trigger the forwarding of VPN traffic to an attacker-controlled destination, or the discarding of this traffic, by arranging for an arbitrary device to become a cluster member, aka Bug ID CSCub93641.