A vulnerability in the DHCP processing functionality of Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to the improper processing of DHCP messages. An attacker could exploit this vulnerability by sending malicious DHCP messages 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 UDP processing functionality of Cisco IOS XE Software for Embedded Wireless Controllers on Catalyst 9100 Series Access Points could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to the improper processing of UDP datagrams. An attacker could exploit this vulnerability by sending malicious UDP datagrams to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.

On April 20, 2022, the following vulnerability in the ClamAV scanning library versions 0.103.5 and earlier and 0.104.2 and earlier was disclosed: A vulnerability in the TIFF file parser of Clam AntiVirus (ClamAV) versions 0.104.0 through 0.104.2 and LTS version 0.103.5 and prior versions could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device. For a description of this vulnerability, see the ClamAV blog. This advisory will be updated as additional information becomes available.

A vulnerability in the Control and Provisioning of Wireless Access Points (CAPWAP) protocol processing of Cisco IOS XE Wireless Controller Software for the Catalyst 9000 Family could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to inadequate input validation of incoming CAPWAP packets encapsulating multicast DNS (mDNS) queries. An attacker could exploit this vulnerability by connecting to a wireless network and sending a crafted mDNS query, which would flow through and be processed by the wireless controller. A successful exploit could allow the attacker to cause the affected device to crash and reload, resulting in a DoS condition.

A vulnerability in the RADIUS feature of Cisco Identity Services Engine (ISE) could allow an unauthenticated, remote attacker to cause the affected system to stop processing RADIUS packets. This vulnerability is due to improper handling of certain RADIUS requests. An attacker could exploit this vulnerability by attempting to authenticate to a network or a service where the access server is using Cisco ISE as the RADIUS server. A successful exploit could allow the attacker to cause Cisco ISE to stop processing RADIUS requests, causing authentication/authorization timeouts, which would then result in legitimate requests being denied access. Note: To recover the ability to process RADIUS packets, a manual restart of the affected Policy Service Node (PSN) is required. See the Details section for more information.

On April 20, 2022, the following vulnerability in the ClamAV scanning library versions 0.103.5 and earlier and 0.104.2 and earlier was disclosed: A vulnerability in CHM file parser of Clam AntiVirus (ClamAV) versions 0.104.0 through 0.104.2 and LTS version 0.103.5 and prior versions could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device. For a description of this vulnerability, see the ClamAV blog. This advisory will be updated as additional information becomes available.

A vulnerability in IP ingress packet processing of the Cisco Embedded Wireless Controller with Catalyst Access Points Software could allow an unauthenticated, remote attacker to cause the device to reload unexpectedly, causing a denial of service (DoS) condition. The device may experience a performance degradation in traffic processing or high CPU usage prior to the unexpected reload. This vulnerability is due to improper rate limiting of IP packets to the management interface. An attacker could exploit this vulnerability by sending a steady stream of IP traffic at a high rate to the management interface of the affected device. A successful exploit could allow the attacker to cause the device to reload.

The IKEv2 implementation in Cisco ASA Software 8.4 before 8.4(7.15), 8.6 before 8.6(1.14), 9.0 before 9.0(4.8), and 9.1 before 9.1(5.1) allows remote attackers to cause a denial of service (device reload) via a crafted packet that is sent during tunnel creation, aka Bug ID CSCum96401.

A vulnerability in the rate limiter for Bidirectional Forwarding Detection (BFD) traffic of Cisco NX-OS Software for Cisco Nexus 9000 Series Switches could allow an unauthenticated, remote attacker to cause BFD traffic to be dropped on an affected device. This vulnerability is due to a logic error in the BFD rate limiter functionality. An attacker could exploit this vulnerability by sending a crafted stream of traffic through the device. A successful exploit could allow the attacker to cause BFD traffic to be dropped, resulting in BFD session flaps. BFD session flaps can cause route instability and dropped traffic, resulting in a denial of service (DoS) condition. This vulnerability applies to both IPv4 and IPv6 traffic.

Memory leak in Cisco IOS 12.4, 15.0, and 15.1, and IOS XE 2.5.x through 3.2.x, allows remote attackers to cause a denial of service (memory consumption) via a crafted SIP message, aka Bug ID CSCti48504.

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.

Cisco Firewall Services Module (aka FWSM) 3.1 before 3.1(21), 3.2 before 3.2(22), 4.0 before 4.0(16), and 4.1 before 4.1(7), when certain authentication configurations are used, allows remote attackers to cause a denial of service (module crash) by making many authentication requests for network access, aka Bug ID CSCtn15697.

Cisco Unified Presence before 8.5(4) does not properly detect recursion during entity expansion, which allows remote attackers to cause a denial of service (memory and CPU consumption, and process crash) via a crafted XML document containing a large number of nested entity references, aka Bug IDs CSCtq89842 and CSCtq88547, a similar issue to CVE-2003-1564.

A vulnerability in the Cisco Fabric Services over IP (CFSoIP) feature of Cisco NX-OS 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 incoming CFSoIP packets. An attacker could exploit this vulnerability by sending crafted CFSoIP packets to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

A vulnerability in the system resource management of Cisco Elastic Services Controller (ESC) could allow an unauthenticated, remote attacker to cause a denial of service (DoS) to the health monitor API on an affected device. The vulnerability is due to inadequate provisioning of kernel parameters for the maximum number of TCP connections and SYN backlog. An attacker could exploit this vulnerability by sending a flood of crafted TCP packets to an affected device. A successful exploit could allow the attacker to block TCP listening ports that are used by the health monitor API. This vulnerability only affects customers who use the health monitor API.

The SSL VPN (aka WebVPN) feature in Cisco IOS 15.1 through 15.4 allows remote attackers to cause a denial of service (memory consumption) via crafted HTTP requests, aka Bug ID CSCuf51357.

Unspecified vulnerability in Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 6.x before 6.1(5)su2, 7.x before 7.1(5b)su3, 8.x before 8.0(3a)su1, and 8.5 before 8.5(1) allows remote attackers to cause a denial of service (service outage) via a SIP INVITE message, aka Bug ID CSCth43256.

The Packet Capture Service in Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 4.x does not properly handle idle TCP connections, which allows remote attackers to cause a denial of service (memory consumption and restart) by making many connections, aka Bug ID CSCtf97162.

Unspecified vulnerability in the Service Advertisement Framework (SAF) in Cisco Unified Communications Manager (aka CUCM, formerly CallManager) 8.x before 8.5(1) and Cisco Intercompany Media Engine 8.x before 8.5(1) allows remote attackers to cause a denial of service (device reload) via crafted SAF packets, aka Bug ID CSCth26669.

Cisco IOS 12.2(58)SE, when a login banner is configured, allows remote attackers to cause a denial of service (device reload) by establishing two SSH2 sessions, aka Bug ID CSCto62631.

Cisco IOS XR 3.6.x, 3.8.x before 3.8.3, and 3.9.x before 3.9.1 does not properly remove sshd_lock files from /tmp/, which allows remote attackers to cause a denial of service (disk consumption) by making many SSHv1 connections, aka Bug ID CSCtd64417.

Multiple vulnerabilities in Cisco SD-WAN products could allow an unauthenticated, remote attacker to execute denial of service (DoS) attacks against an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

Cisco IOS XR 3.9.x and 4.0.x before 4.0.3 and 4.1.x before 4.1.1, when an SPA interface processor is installed, allows remote attackers to cause a denial of service (device reload) via a crafted IPv4 packet, aka Bug ID CSCto45095.

Memory leak in Cisco Unified Communications Manager (CUCM) 6.x before 6.1(5)su2, 7.x before 7.1(5b)su3, 8.x before 8.0(3a)su1, and 8.5 before 8.5(1), and Cisco IOS 12.4 and 15.1, allows remote attackers to cause a denial of service (memory consumption and process failure or device reload) via a malformed SIP message, aka Bug IDs CSCti75128 and CSCtj09179.

Cisco Nexus 1000V Virtual Ethernet Module (VEM) 4.0(4) SV1(1) through SV1(3b), as used in VMware ESX 4.0 and 4.1 and ESXi 4.0 and 4.1, does not properly handle dropped packets, which allows guest OS users to cause a denial of service (ESX or ESXi host OS crash) by sending an 802.1Q tagged packet over an access vEthernet port, aka Cisco Bug ID CSCtj17451.

Cisco IOS 12.2 and 15.0 through 15.3 allows remote attackers to cause a denial of service (traffic-processing outage) via a crafted series of Common Industrial Protocol (CIP) requests, aka Bug ID CSCur69036.

Buffer overflow in the web-based management interface on the Cisco Linksys WRT54GC router with firmware before 1.06.1 allows remote attackers to cause a denial of service (device crash) via a long string in a POST request.

Cisco TelePresence endpoint devices with software 1.2.x through 1.6.x allow remote attackers to cause a denial of service (service crash) via a malformed SOAP request in conjunction with a spoofed TelePresence Manager that supplies an invalid IP address, aka Bug ID CSCth03605.

CallManager Express (CME) on Cisco IOS before 15.0(1)XA1 does not properly handle SIP TRUNK traffic that contains rate bursts and a "peculiar" request size, which allows remote attackers to cause a denial of service (memory consumption) by sending this traffic over a long duration, aka Bug ID CSCtb47950.

Unspecified vulnerability on Cisco Adaptive Security Appliances (ASA) 5500 series devices with software 8.2(4) and earlier allows remote attackers to cause a denial of service (block exhaustion) via multicast traffic, aka Bug ID CSCtg63992.

Cisco Unified Personal Communicator 7.0 (1.13056) does not free allocated memory for received data and does not perform validation if memory allocation is successful, causing a remote denial of service condition.

Unspecified vulnerability in the H.323 implementation in Cisco IOS 12.1 through 12.4 and 15.0 through 15.1, and IOS XE 2.5.x before 2.5.2 and 2.6.x before 2.6.1, allows remote attackers to cause a denial of service (traceback and device reload) via crafted H.323 packets, aka Bug ID CSCtd33567.

Unspecified vulnerability in the Transport Layer Security (TLS) implementation on Cisco Adaptive Security Appliances (ASA) 5500 series devices with software 7.2 before 7.2(5), 8.0 before 8.0(5.15), 8.1 before 8.1(2.44), 8.2 before 8.2(2.17), and 8.3 before 8.3(1.6) and Cisco PIX Security Appliances 500 series devices allows remote attackers to cause a denial of service (device reload) via a sequence of crafted TLS packets, aka Bug ID CSCtf37506.

Unspecified vulnerability in the H.323 implementation in Cisco IOS 12.1 through 12.4 and 15.0 through 15.1, and IOS XE 2.5.x before 2.5.2 and 2.6.x before 2.6.1, allows remote attackers to cause a denial of service (device reload) via crafted H.323 packets, aka Bug ID CSCtc73759.

Unspecified vulnerability on the Cisco Application Control Engine (ACE) Module with software A2(1.x) before A2(1.6), A2(2.x) before A2(2.3), and A2(3.x) before A2(3.1) for Catalyst 6500 series switches and 7600 series routers allows remote attackers to cause a denial of service (device reload) via a sequence of SSL packets, aka Bug ID CSCta20756.

Cisco Unified Wireless Network (UWN) Solution 7.x before 7.0.98.0 on 5508 series controllers allows remote attackers to cause a denial of service (buffer leak and device crash) via ARP requests that trigger an ARP storm, aka Bug ID CSCte43508.

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

A vulnerability in the TCP proxy functionality of 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 handling of TCP flows. An attacker could exploit this vulnerability by sending a crafted stream of TCP traffic through 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 Snort rule evaluation function of Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper handling of the DNS reputation enforcement rule. An attacker could exploit this vulnerability by sending crafted UDP packets through an affected device to force a buildup of UDP connections. A successful exploit could allow the attacker to cause traffic that is going through the affected device to be dropped, resulting in a DoS condition. Note: This vulnerability only affects Cisco FTD devices that are running Snort 3.

A vulnerability in the OLE2 file parser of Clam AntiVirus (ClamAV) versions 0.104.0 through 0.104.2 could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device.The vulnerability is due to incorrect use of the realloc function that may result in a double-free. An attacker could exploit this vulnerability by submitting a crafted OLE2 file to be scanned by ClamAV on the affected device. An exploit could allow the attacker to cause the ClamAV scanning process to crash, resulting in a denial of service condition.

A vulnerability in the connection handling function in 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 improper traffic handling when platform limits are reached. An attacker could exploit this vulnerability by sending a high rate of UDP traffic through an affected device. A successful exploit could allow the attacker to cause all new, incoming connections to be dropped, resulting in a DoS condition.

On April 20, 2022, the following vulnerability in the ClamAV scanning library versions 0.103.5 and earlier and 0.104.2 and earlier was disclosed: A vulnerability in HTML file parser of Clam AntiVirus (ClamAV) versions 0.104.0 through 0.104.2 and LTS version 0.103.5 and prior versions could allow an unauthenticated, remote attacker to cause a denial of service condition on an affected device. For a description of this vulnerability, see the ClamAV blog. This advisory will be updated as additional information becomes available.

The MGCP implementation on the Cisco PGW 2200 Softswitch with software before 9.7(3)S11 allows remote attackers to cause a denial of service (device crash) via a malformed packet, aka Bug ID CSCsl39126.

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 an API of the Call Bridge feature of Cisco Meeting Server could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. This vulnerability is due to improper handling of large series of message requests. An attacker could exploit this vulnerability by sending a series of messages to the vulnerable API. A successful exploit could allow the attacker to cause the affected device to reload, dropping all ongoing calls and resulting in a DoS condition.

Multiple vulnerabilities in the Cisco IOx application hosting environment on multiple Cisco platforms could allow an attacker to inject arbitrary commands into the underlying host operating system, execute arbitrary code on the underlying host operating system, install applications without being authenticated, or conduct a cross-site scripting (XSS) attack against a user of the affected software. For more information about these vulnerabilities, see the Details section of this advisory.