A vulnerability within the Endpoint Learning feature of Cisco Nexus 9000 Series Switches running in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an endpoint device in certain circumstances. The vulnerability is due to improper endpoint learning when packets are received on a specific port from outside the ACI fabric and destined to an endpoint located on a border leaf when Disable Remote Endpoint Learning has been enabled. This can result in a Remote (XR) entry being created for the impacted endpoint that will become stale if the endpoint migrates to a different port or leaf switch. This results in traffic not reaching the impacted endpoint until the Remote entry can be relearned by another mechanism.

Cisco Unified Wireless Network (UWN) Solution 7.x before 7.0.98.0 allows remote attackers to cause a denial of service (device crash) by pinging a virtual interface, aka Bug ID CSCte55370.

The IGMPv3 implementation in Cisco IOS 12.2, 12.3, 12.4, and 15.0 and IOS XE 2.5.x before 2.5.2, when PIM is enabled, allows remote attackers to cause a denial of service (device reload) via a malformed IGMP packet, aka Bug ID CSCte14603.

Unspecified vulnerability on the Cisco Firewall Services Module (FWSM) with software 3.2 before 3.2(17.2), 4.0 before 4.0(11.1), and 4.1 before 4.1(1.2) for Catalyst 6500 series switches and 7600 series routers, when multi-mode is enabled, allows remote attackers to cause a denial of service (device reload) via crafted (1) Telnet, (2) SSH, or (3) ASDM traffic over TCP, aka Bug ID CSCtg68694.

The SIP process in Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 7.x before 7.1(5b)su4 and 8.x before 8.0(1) does not properly handle SDP data within a SIP call in certain situations related to use of the g729ar8 codec for a Media Termination Point (MTP), which allows remote attackers to cause a denial of service (service outage) via a crafted call, aka Bug ID CSCtc61990.

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.

A vulnerability in the IPv6 DHCP (DHCPv6) client module of Cisco Adaptive Security Appliance (ASA) Software, Cisco Firepower Threat Defense (FTD) Software, Cisco IOS Software, and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient validation of DHCPv6 messages. An attacker could exploit this vulnerability by sending crafted DHCPv6 messages to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition. Note: To successfully exploit this vulnerability, the attacker would need to either control the DHCPv6 server or be in a man-in-the-middle position.

Unspecified vulnerability in Cisco ASA 5500 Series Adaptive Security Appliance 7.0 before 7.0(8.10), 7.2 before 7.2(4.45), 8.0 before 8.0(4.44), 8.1 before 8.1(2.35), and 8.2 before 8.2(1.10) allows remote attackers to cause a denial of service (device reload) via a malformed TCP segment when certain NAT translation and Cisco AIP-SSM configurations are used, aka Bug ID CSCtb37219.

Cisco IOS 12.2 through 12.4, when certain PMTUD, SNAT, or window-size configurations are used, allows remote attackers to cause a denial of service (infinite loop, and device reload or hang) via a TCP segment with crafted options, aka Bug ID CSCsz75186.

Cisco NX-OS 4.0 through 7.3 and 11.0 through 11.2 on 1000v, 2000, 3000, 3500, 5000, 5500, 5600, 6000, 7000, 7700, and 9000 devices allows remote attackers to cause a denial of service (device reload) by leveraging a peer relationship to send a crafted BGP UPDATE message, aka Bug IDs CSCuq77105 and CSCux11417.

The IKEv2 implementation in Cisco IOS 15.0 through 15.6 and IOS XE 3.3 through 3.17 allows remote attackers to cause a denial of service (device reload) via fragmented packets, aka Bug ID CSCux38417.

The kernel in Cisco TelePresence Server 3.0 through 4.2(4.18) on Mobility Services Engine (MSE) 8710 devices allows remote attackers to cause a denial of service (panic and reboot) via a crafted sequence of IPv6 packets, aka Bug ID CSCuu46673.

The UDP inspection engine on Cisco Adaptive Security Appliances (ASA) 5500 series devices, and the ASA Services Module (ASASM) in Cisco Catalyst 6500 series devices, with software 8.0 before 8.0(5.25), 8.1 before 8.1(2.50), 8.2 before 8.2(5.5), 8.3 before 8.3(2.22), 8.4 before 8.4(2.1), and 8.5 before 8.5(1.2) does not properly handle flows, which allows remote attackers to cause a denial of service (device reload) via a crafted series of (1) IPv4 or (2) IPv6 UDP packets, aka Bug ID CSCtq10441.

A vulnerability in the access point (AP) joining process of the Control and Provisioning of Wireless Access Points (CAPWAP) protocol of Cisco IOS XE Software for Wireless LAN Controllers (WLCs) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to a logic error that occurs when certain conditions are met during the AP joining process. An attacker could exploit this vulnerability by adding an AP that is under their control to the network. The attacker then must ensure that the AP successfully joins an affected wireless controller under certain conditions. Additionally, the attacker would need the ability to restart a valid AP that was previously connected to the controller. A successful exploit could allow the attacker to cause the affected device to restart unexpectedly, resulting in a DoS condition.

Cisco IOS 12.0 through 12.4, when IP-based tunnels and the Cisco Express Forwarding feature are enabled, allows remote attackers to cause a denial of service (device reload) via malformed packets, aka Bug ID CSCsx70889.

The (1) Cisco Unified Communications Manager Express; (2) SIP Gateway Signaling Support Over Transport Layer Security (TLS) Transport; (3) Secure Signaling and Media Encryption; (4) Blocks Extensible Exchange Protocol (BEEP); (5) Network Admission Control HTTP Authentication Proxy; (6) Per-user URL Redirect for EAPoUDP, Dot1x, and MAC Authentication Bypass; (7) Distributed Director with HTTP Redirects; and (8) TCP DNS features in Cisco IOS 12.0 through 12.4 do not properly handle IP sockets, which allows remote attackers to cause a denial of service (outage or resource consumption) via a series of crafted TCP packets.

Multiple unspecified vulnerabilities in the home agent (HA) implementation in the (1) Mobile IP NAT Traversal feature and (2) Mobile IPv6 subsystem in Cisco IOS 12.3 through 12.4 allow remote attackers to cause a denial of service (input queue wedge and interface outage) via an ICMP packet, aka Bug ID CSCso05337.

Cisco IOS 12.0(32)S12 through 12.0(32)S13 and 12.0(33)S3 through 12.0(33)S4, 12.0(32)SY8 through 12.0(32)SY9, 12.2(33)SXI1, 12.2XNC before 12.2(33)XNC2, 12.2XND before 12.2(33)XND1, and 12.4(24)T1; and IOS XE 2.3 through 2.3.1t and 2.4 through 2.4.0; when RFC4893 BGP routing is enabled, allows remote attackers to cause a denial of service (memory corruption and device reload) by using an RFC4271 peer to send an update with a long series of AS numbers, aka Bug ID CSCsy86021.

Multiple unspecified vulnerabilities in the (1) Mobile IP NAT Traversal feature and (2) Mobile IPv6 subsystem in Cisco IOS 12.3 through 12.4 allow remote attackers to cause a denial of service (input queue wedge and interface outage) via MIPv6 packets, aka Bug ID CSCsm97220.

A vulnerability in the IKEv1 fragmentation code of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a heap overflow, resulting in an affected device reloading. This vulnerability exists because crafted, fragmented IKEv1 packets are not properly reassembled. An attacker could exploit this vulnerability by sending crafted UDP packets to an affected system. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Note: Only traffic that is directed to the affected system can be used to exploit this vulnerability. This vulnerability can be triggered by IPv4 and IPv6 traffic.

A vulnerability in the session authentication functionality of the Remote Access SSL VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to prevent users from authenticating. This vulnerability is due to insufficient entropy in the authentication process. An attacker could exploit this vulnerability by determining the handle of an authenticating user and using it to terminate their authentication session. A successful exploit could allow the attacker to force a user to restart the authentication process, preventing a legitimate user from establishing remote access VPN sessions.

Cisco Unified Computing System (UCS) 2.2(3f)A on Fabric Interconnect 6200 devices allows remote attackers to cause a denial of service (CPU consumption or device outage) via a SYN flood on the SSH port during the booting process, aka Bug ID CSCuu81757.

The DHCPv6 relay implementation in Cisco Adaptive Security Appliance (ASA) software 9.0 before 9.0(4.37), 9.1 before 9.1(6.6), 9.2 before 9.2(4), 9.3 before 9.3(3.5), and 9.4 before 9.4(2) allows remote attackers to cause a denial of service (device reload) via crafted DHCPv6 packets, aka Bug IDs CSCus56252 and CSCus57142.

A vulnerability in the web services interface of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper input validation when parsing HTTPS requests. An attacker could exploit this vulnerability by sending a malicious HTTPS request to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

Cisco Adaptive Security Appliance (ASA) software 7.2 and 8.2 before 8.2(5.58), 8.3 and 8.4 before 8.4(7.29), 8.5 through 8.7 before 8.7(1.17), 9.0 before 9.0(4.37), 9.1 before 9.1(6.4), 9.2 before 9.2(4), 9.3 before 9.3(3.1), and 9.4 before 9.4(1.1) allows remote attackers to cause a denial of service (device reload) via a crafted DNS response, aka Bug ID CSCut03495.

Race condition in the IPv6-to-IPv4 functionality in Cisco IOS 15.3S in the Performance Routing Engine (PRE) module on UBR devices allows remote attackers to cause a denial of service (NULL pointer free and module crash) by triggering intermittent connectivity with many IPv6 CPE devices, aka Bug ID CSCug47366.

A vulnerability in the TCP syslog module of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to exhaust the 1550-byte buffers on an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a missing boundary check in an internal function. An attacker could exploit this vulnerability by establishing a man-in-the-middle position between an affected device and its configured TCP syslog server and then maliciously modifying the TCP header in segments that are sent from the syslog server to the affected device. A successful exploit could allow the attacker to exhaust buffer on the affected device and cause all TCP-based features to stop functioning, resulting in a DoS condition. The affected TCP-based features include AnyConnect SSL VPN, clientless SSL VPN, and management connections such as Secure Shell (SSH), Telnet, and HTTPS.

A vulnerability in the implementation of Traffic Flow Confidentiality (TFC) over IPsec functionality in Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to restart unexpectedly, resulting in a denial of service (DoS) condition. The vulnerability is due to an error that may occur if the affected software renegotiates the encryption key for an IPsec tunnel when certain TFC traffic is in flight. An attacker could exploit this vulnerability by sending a malicious stream of TFC traffic through an established IPsec tunnel on an affected device. A successful exploit could allow the attacker to cause a daemon process on the affected device to crash, which could cause the device to crash and result in a DoS condition.

A vulnerability in the implementation of Border Gateway Protocol (BGP) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain BGP update messages. An attacker could exploit this vulnerability by sending BGP update messages that include a specific, malformed attribute to be processed by an affected system. A successful exploit could allow the attacker to cause the BGP process to restart unexpectedly, resulting in a DoS condition. The Cisco implementation of BGP accepts incoming BGP traffic only from explicitly defined peers. To exploit this vulnerability, the malicious BGP update message would need to come from a configured, valid BGP peer, or would need to be injected by the attacker into the victim's BGP network on an existing, valid TCP connection to a BGP peer.

A vulnerability in the FTP inspection engine of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerability exists because the affected software fails to release spinlocks when a device is running low on system memory, if the software is configured to apply FTP inspection and an access control rule to transit traffic, and the access control rule is associated with an FTP file policy. An attacker could exploit this vulnerability by sending a high rate of transit traffic through an affected device to cause a low-memory condition on the device. A successful exploit could allow the attacker to cause a software panic on the affected device, which could cause the device to reload and result in a temporary DoS condition.

A vulnerability in the AnyConnect SSL VPN feature of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an implementation error within the SSL/TLS session handling process that can prevent the release of a session handler under specific conditions. An attacker could exploit this vulnerability by sending crafted SSL/TLS traffic to an affected device, increasing the probability of session handler leaks. A successful exploit could allow the attacker to eventually deplete the available session handler pool, preventing new sessions from being established and causing a DoS condition.

Cisco IOS XR 5.0.1 and 5.2.1 on Network Convergence System (NCS) 6000 devices and 5.1.3 and 5.1.4 on Carrier Routing System X (CRS-X) devices allows remote attackers to cause a denial of service (line-card reload) via malformed IPv6 packets with extension headers, aka Bug ID CSCuq95241.

The TFTP server in Cisco IOS 12.2(44)SQ1, 12.2(33)XN1, 12.4(25e)JAM1, 12.4(25e)JAO5m, 12.4(23)JY, 15.0(2)ED1, 15.0(2)EY3, 15.1(3)SVF4a, and 15.2(2)JB1 and IOS XE 2.5.x, 2.6.x, 3.1.xS, 3.2.xS, 3.3.xS, 3.4.xS, and 3.5.xS before 3.6.0S; 3.1.xSG, 3.2.xSG, and 3.3.xSG before 3.4.0SG; 3.2.xSE before 3.3.0SE; 3.2.xXO before 3.3.0XO; 3.2.xSQ; 3.3.xSQ; and 3.4.xSQ allows remote attackers to cause a denial of service (device hang or reload) via multiple requests that trigger improper memory management, aka Bug ID CSCts66733.

The Connection Conversation Manager (aka CuCsMgr) process in Cisco Unity Connection 8.5 before 8.5(1)SU7, 8.6 before 8.6(2a)SU4, 9.x before 9.1(2)SU2, and 10.0 before 10.0(1)SU1, when SIP trunk integration is enabled, allows remote attackers to cause a denial of service (core dump and restart) via crafted SIP INVITE messages, aka Bug ID CSCul20444.

The Connection Conversation Manager (aka CuCsMgr) process in Cisco Unity Connection 8.5 before 8.5(1)SU6, 8.6 before 8.6(2a)SU4, and 9.x before 9.1(2)SU2, when SIP trunk integration is enabled, allows remote attackers to cause a denial of service (SIP outage) via a crafted UDP packet, aka Bug ID CSCuh25062.

Cisco IOS XE 3.10.2S on an ASR 1000 device with an Embedded Services Processor (ESP) module, when NAT is enabled, allows remote attackers to cause a denial of service (module crash) via malformed H.323 packets, aka Bug ID CSCup21070.

Race condition in the TLS implementation in MainApp in the management interface in Cisco Intrusion Prevention System (IPS) Software before 7.3(3)E4 allows remote attackers to cause a denial of service (process hang) by establishing many HTTPS sessions, aka Bug ID CSCuq40652.

Cisco TelePresence Video Communication Server (VCS) X8.5RC4 allows remote attackers to cause a denial of service (CPU consumption or device outage) via a crafted SDP parameter-negotiation request in an SDP session during a SIP connection, aka Bug ID CSCut42422.

The Connection Conversation Manager (aka CuCsMgr) process in Cisco Unity Connection 8.5 before 8.5(1)SU7, 8.6 before 8.6(2a)SU4, and 9.x before 9.1(2)SU2, when SIP trunk integration is enabled, allows remote attackers to cause a denial of service (core dump and restart) by improperly terminating SIP TCP connections, aka Bug ID CSCul69819.

Memory leak in the Cisco Tunneling Control Protocol (cTCP) encapsulation feature in Cisco IOS 12.4, when an Easy VPN (aka EZVPN) server is enabled, allows remote attackers to cause a denial of service (memory consumption and device crash) via a sequence of TCP packets.

The Connection Conversation Manager (aka CuCsMgr) process in Cisco Unity Connection 8.5 before 8.5(1)SU7, 8.6 before 8.6(2a)SU4, 9.x before 9.1(2)SU2, and 10.0 before 10.0(1)SU1, when SIP trunk integration is enabled, allows remote attackers to cause a denial of service (core dump and restart) via crafted SIP INVITE messages, aka Bug ID CSCul26267.

Cisco IOS 12.2, 12.4, 15.0, 15.2, and 15.3, when a VRF interface is configured, allows remote attackers to cause a denial of service (interface queue wedge) via crafted ICMPv4 packets, aka Bug ID CSCsi02145.

The Zone-Based Firewall implementation in Cisco IOS 12.4(122)T and earlier does not properly manage session-object structures, which allows remote attackers to cause a denial of service (device reload) via crafted network traffic, aka Bug ID CSCul65003.

The TCP implementation in (1) Linux, (2) platforms based on BSD Unix, (3) Microsoft Windows, (4) Cisco products, and probably other operating systems allows remote attackers to cause a denial of service (connection queue exhaustion) via multiple vectors that manipulate information in the TCP state table, as demonstrated by sockstress.