The DNS implementation in Cisco Adaptive Security Appliance (ASA) Software 7.2 before 7.2(5.16), 8.2 before 8.2(5.57), 8.3 before 8.3(2.44), 8.4 before 8.4(7.28), 8.5 before 8.5(1.24), 8.6 before 8.6(1.17), 8.7 before 8.7(1.16), 9.0 before 9.0(4.33), 9.1 before 9.1(6.1), 9.2 before 9.2(3.4), and 9.3 before 9.3(3) allows man-in-the-middle attackers to cause a denial of service (memory consumption or device outage) by triggering outbound DNS queries and then sending crafted responses to these queries, aka Bug ID CSCuq77655.

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 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 call-handling implementation 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 (port consumption) by improperly terminating SIP sessions, aka Bug ID CSCul28089.

Race condition in the SSL implementation on Cisco Intrusion Prevention System (IPS) devices allows remote attackers to cause a denial of service by making many management-interface HTTPS connections during the key-regeneration phase of an upgrade, aka Bug ID CSCui25688.

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.

A vulnerability in the implementation of the Border Gateway Protocol (BGP) Ethernet VPN (EVPN) functionality in Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to the incorrect processing of a BGP update message that contains specific EVPN attributes. An attacker could exploit this vulnerability by sending a BGP update message that contains specific EVPN attributes. To exploit this vulnerability, an attacker must control a BGP speaker that has an established trusted peer connection to an affected device that is configured with the address family L2VPN EVPN to receive and process the update message. This vulnerability cannot be exploited by any data that is initiated by clients on the Layer 2 network or by peers that are not configured to accept the L2VPN EVPN address family. 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 updates only from explicitly defined peers. For this vulnerability to be exploited, the malicious BGP update message must either come from a configured, valid BGP peer or be injected by the attacker into the affected BGP network on an existing, valid TCP connection to a BGP peer.

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.

A vulnerability in the DNS-based Authentication of Named Entities (DANE) email verification component of Cisco AsyncOS Software for Cisco Email Security Appliance (ESA) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient error handling in DNS name resolution by the affected software. An attacker could exploit this vulnerability by sending specially formatted email messages that are processed by an affected device. A successful exploit could allow the attacker to cause the device to become unreachable from management interfaces or to process additional email messages for a period of time until the device recovers, resulting in a DoS condition. Continued attacks could cause the device to become completely unavailable, resulting in a persistent DoS condition.

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 Wireless Intrusion Detection (aka WIDS) functionality on Cisco Wireless LAN Controller (WLC) devices allows remote attackers to cause a denial of service (device outage) via crafted packets that are improperly handled during rendering of the Signature Events Summary page, aka Bug ID CSCus46861.

Multiple vulnerabilities in the Login Enhancements (Login Block) feature of Cisco IOS Software could allow an unauthenticated, remote attacker to trigger a reload of an affected system, resulting in a denial of service (DoS) condition. These vulnerabilities affect Cisco devices that are running Cisco IOS Software Release 15.4(2)T, 15.4(3)M, or 15.4(2)CG and later. Cisco Bug IDs: CSCuy32360, CSCuz60599.

Cisco IOS on Aironet access points, when "dot11 aaa authenticator" debugging is enabled, allows remote attackers to cause a denial of service via a malformed EAP packet, aka Bug ID CSCul15509.

Cisco TelePresence System MXP Series Software before F9.3.1 allows remote attackers to cause a denial of service (device reload) via crafted SIP packets, aka Bug ID CSCty45739.

A vulnerability in the implementation of the Resource Public Key Infrastructure (RPKI) feature of Cisco IOS XR Software could allow an unauthenticated, remote attacker to cause the Border Gateway Protocol (BGP) process to crash, resulting in a denial of service (DoS) condition. This vulnerability is due to the incorrect handling of a specific RPKI to Router (RTR) Protocol packet header. An attacker could exploit this vulnerability by compromising the RPKI validator server and sending a specifically crafted RTR packet to an affected device. Alternatively, the attacker could use man-in-the-middle techniques to impersonate the RPKI validator server and send a specifically crafted RTR response packet over the established RTR TCP connection to the affected device. A successful exploit could allow the attacker to cause a DoS condition because the BGP process could constantly restart and BGP routing could become unstable.Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.This advisory is part of the September 2021 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see .

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.

A vulnerability in the DNS application layer gateway (ALG) functionality used by Network Address Translation (NAT) in Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to a logic error that occurs when an affected device inspects certain DNS packets. An attacker could exploit this vulnerability by sending crafted DNS packets through an affected device that is performing NAT for DNS packets. A successful exploit could allow an attacker to cause the device to reload, resulting in a denial of service (DoS) condition on an affected device. The vulnerability can be exploited only by traffic that is sent through an affected device via IPv4 packets. The vulnerability cannot be exploited via IPv6 traffic.

A vulnerability in the web UI feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to conduct a cross-site WebSocket hijacking (CSWSH) attack and cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient HTTP protections in the web UI on an affected device. An attacker could exploit this vulnerability by persuading an authenticated user of the web UI to follow a crafted link. A successful exploit could allow the attacker to corrupt memory on the affected device, forcing it to reload and causing a DoS condition.

Cisco IPS Software 7.1 before 7.1(8)E4 and 7.2 before 7.2(2)E4 allows remote attackers to cause a denial of service (Analysis Engine process outage) via a flood of jumbo frames, aka Bug ID CSCuh94944.

A vulnerability in the Secure Login Enhancements capability of Cisco Nexus 1000V Switch for VMware vSphere could allow an unauthenticated, remote attacker to cause an affected Nexus 1000V Virtual Supervisor Module (VSM) to become inaccessible to users through the CLI. The vulnerability is due to improper resource allocation during failed CLI login attempts when login parameters that are part of the Secure Login Enhancements capability are configured on an affected device. An attacker could exploit this vulnerability by performing a high amount of login attempts against the affected device. A successful exploit could cause the affected device to become inaccessible to other users, resulting in a denial of service (DoS) condition requiring a manual power cycle of the VSM to recover.

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 Cisco AMP for Endpoints Mac Connector Software installed on Apple macOS 10.12 could allow an unauthenticated, remote attacker to cause a kernel panic on an affected system, resulting in a denial of service (DoS) condition. The vulnerability exists if the affected software is running in Block network conviction mode. Exploitation could occur if the system that is running the affected software starts a server process and an address in the IP blacklist cache of the affected software attempts to connect to the affected system. A successful exploit could allow the attacker to cause a kernel panic on the system that is running the affected software, resulting in a DoS condition. Cisco Bug IDs: CSCvk08192.

A vulnerability in the Network Address Translation (NAT) Session Initiation Protocol (SIP) Application Layer Gateway (ALG) of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to improper processing of SIP packets in transit while NAT is performed on an affected device. An unauthenticated, remote attacker could exploit this vulnerability by sending crafted SIP packets via UDP port 5060 through an affected device that is performing NAT for SIP packets. A successful exploit could allow an attacker to cause the device to reload, resulting in a denial of service (DoS) condition.

Cisco IOS before 15.0(1)XA1, when certain TFTP debugging is enabled, allows remote attackers to cause a denial of service (device crash) via a TFTP copy over IPv6, aka Bug ID CSCtb28877.

A vulnerability in the TCP socket code of Cisco IOS and IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to a state condition between the socket state and the transmission control block (TCB) state. While this vulnerability potentially affects all TCP applications, the only affected application observed so far is the HTTP server. An attacker could exploit this vulnerability by sending specific HTTP requests at a sustained rate to a reachable IP address of the affected software. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition on an affected device.

A vulnerability in the web user interface of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. The vulnerability is due to a double-free-in-memory handling by the affected software when specific HTTP requests are processed. An attacker could exploit this vulnerability by sending specific HTTP requests to the web user interface of the affected software. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service (DoS) condition on an affected device. To exploit this vulnerability, the attacker must have access to the management interface of the affected software, which is typically connected to a restricted management network.

Multiple vulnerabilities in the Login Enhancements (Login Block) feature of Cisco IOS Software could allow an unauthenticated, remote attacker to trigger a reload of an affected system, resulting in a denial of service (DoS) condition. These vulnerabilities affect Cisco devices that are running Cisco IOS Software Release 15.4(2)T, 15.4(3)M, or 15.4(2)CG and later. Cisco Bug IDs: CSCuy32360, CSCuz60599.

A vulnerability in the Forwarding Information Base (FIB) code of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, network attacker to cause a denial of service (DoS) condition. The vulnerability is due to a limitation in the way the FIB is internally representing recursive routes. An attacker could exploit this vulnerability by injecting routes into the routing protocol that have a specific recursive pattern. The attacker must be in a position on the network that provides the ability to inject a number of recursive routes with a specific pattern. An exploit could allow the attacker to cause an affected device to reload, creating a DoS condition. Cisco Bug IDs: CSCva91655.

A vulnerability with the Border Gateway Protocol (BGP) for Cisco Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode could allow an unauthenticated, remote attacker to cause a routing process to crash, which could lead to a denial of service (DoS) condition. This vulnerability is due to an issue with the installation of routes upon receipt of a BGP update. An attacker could exploit this vulnerability by sending a crafted BGP update to an affected device. A successful exploit could allow the attacker to cause the routing process to crash, which could cause the device to reload. This vulnerability applies to both Internal BGP (IBGP) and External BGP (EBGP). Note: The Cisco implementation of BGP accepts incoming BGP traffic from explicitly configured peers only. To exploit this vulnerability, an attacker would need to send a specific BGP update message over an established TCP connection that appears to come from a trusted BGP peer.

A vulnerability in the detection engine reassembly of Secure Sockets Layer (SSL) packets for Cisco Firepower System Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition because the Snort process consumes a high level of CPU resources. Affected Products: This vulnerability affects Cisco Firepower System Software running software releases 6.0.0, 6.1.0, 6.2.0, or 6.2.1 when the device is configured with an SSL policy that has at least one rule specifying traffic decryption. More Information: CSCvc58563. Known Affected Releases: 6.0.0 6.1.0 6.2.0 6.2.1.

The SIP IX implementation in Cisco TelePresence Video Communication Server (VCS) and Expressway Software before X8.1.1 allows remote attackers to cause a denial of service (device reload) via crafted SDP packets, aka Bug ID CSCuo42252.

Cisco IOS XR 4.3(.2) and earlier, as used in Cisco Carrier Routing System (CRS), allows remote attackers to cause a denial of service (CPU consumption and IPv6 packet drops) via a malformed IPv6 packet, aka Bug ID CSCuo95165.

Race condition in the IP logging feature in Cisco Intrusion Prevention System (IPS) Software 7.1(7)E4 and earlier allows remote attackers to cause a denial of service (device reload) via crafted IP traffic that matches a problematic rule, aka Bug ID CSCud82085.

Cisco TelePresence Video Communication Server (VCS) and Expressway Software before X8.1.1 allow remote attackers to cause a denial of service (device reload) via crafted SIP packets, aka Bug IDs CSCum60442 and CSCum60447.

The ALG module in Cisco IOS 15.0 through 15.4 does not properly implement SIP over NAT, which allows remote attackers to cause a denial of service (device reload) via multipart SDP IPv4 traffic, aka Bug ID CSCun54071.

Cisco IOS XR 4.1.2 through 5.1.1 on ASR 9000 devices, when a Trident-based line card is used, allows remote attackers to cause a denial of service (NP chip and line card reload) via malformed IPv6 packets, aka Bug ID CSCun71928.

Cisco TelePresence System MXP Series Software before F9.3.1 allows remote attackers to cause a denial of service (device reload) via crafted SIP packets, aka Bug ID CSCty45733.

The SIP inspection engine in Cisco Adaptive Security Appliance (ASA) Software 8.2 before 8.2(5.48), 8.4 before 8.4(6.5), 9.0 before 9.0(3.1), and 9.1 before 9.1(2.5) allows remote attackers to cause a denial of service (memory consumption or device reload) via crafted SIP packets, aka Bug ID CSCuh44052.

The Application Layer Gateway (ALG) module in Cisco IOS 12.2 through 12.4 and 15.0 through 15.4, when NAT is used, allows remote attackers to cause a denial of service (device reload) via crafted DNS packets, aka Bug ID CSCue00996.

Cisco IOS 12.2 and 15.0 through 15.3, when used with the Kailash FPGA before 2.6 on RSP720-3C-10GE and RSP720-3CXL-10GE devices, allows remote attackers to cause a denial of service (route switch processor outage) via crafted IP packets, aka Bug ID CSCug84789.

Cisco IOS 15.1(2)SY3 and earlier, when used with Supervisor Engine 2T (aka Sup2T) on Catalyst 6500 devices, allows remote attackers to cause a denial of service (device crash) via crafted multicast packets, aka Bug ID CSCuf60783.

The SIP module in Cisco TelePresence Video Communication Server (VCS) before 8.1 allows remote attackers to cause a denial of service (process failure) via a crafted SDP message, aka Bug ID CSCue97632.

The produce-verbose-alert feature in Cisco IPS Software 7.1 before 7.1(8)E4 and 7.2 before 7.2(2)E4 allows remote attackers to cause a denial of service (Analysis Engine process outage) via fragmented packets, aka Bug ID CSCui91266.

The IGMP implementation on Cisco Wireless LAN Controller (WLC) devices 4.x, 5.x, 6.x, 7.0 before 7.0.250.0, 7.1, 7.2, and 7.3, when IGMPv3 Snooping is enabled, allows remote attackers to cause a denial of service (memory over-read and device restart) via a crafted field in an IGMPv3 message, aka Bug ID CSCuh33240.

Race condition in the cut-through proxy feature in Cisco Firewall Services Module (FWSM) Software 3.x before 3.2(28) and 4.x before 4.1(15) allows remote attackers to cause a denial of service (device reload) via certain matching traffic, aka Bug ID CSCuj16824.

A vulnerability in the SIP inspection process of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a crash and reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to a watchdog timeout and crash during the cleanup of threads that are associated with a SIP connection that is being deleted from the connection list. An attacker could exploit this vulnerability by sending a high rate of crafted SIP traffic through an affected device. A successful exploit could allow the attacker to cause a watchdog timeout and crash, resulting in a crash and reload of the affected device.