A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a DoS condition in the AnyConnect service on an affected device. This vulnerability is due to insufficient resource management when establishing TLS/SSL sessions. An attacker could exploit this vulnerability by sending a series of crafted TLS/SSL messages to the VPN server of an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to stop accepting new connections, preventing new SSL VPN connections from being established. Existing SSL VPN sessions are not impacted. Note: When the attack traffic stops, the Cisco AnyConnect VPN server recovers gracefully without requiring manual intervention.

A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a DoS condition for targeted users of the AnyConnect service on an affected device. This vulnerability is due to insufficient entropy for handlers that are used during SSL VPN session establishment. An unauthenticated attacker could exploit this vulnerability by brute forcing valid session handlers. An authenticated attacker could exploit this vulnerability by connecting to the AnyConnect VPN service of an affected device to retrieve a valid session handler and, based on that handler, predict further valid session handlers. The attacker would then send a crafted HTTPS request using the brute-forced or predicted session handler to the AnyConnect VPN server of the device. A successful exploit could allow the attacker to terminate targeted SSL VPN sessions, forcing remote users to initiate new VPN connections and reauthenticate.

A vulnerability in the Cisco AnyConnect VPN server of Cisco Meraki MX and Cisco Meraki Z Series Teleworker Gateway devices could allow an unauthenticated, remote attacker to cause a DoS condition on an affected device. This vulnerability is due to insufficient resource management while establishing SSL VPN sessions. An attacker could exploit this vulnerability by sending a series of crafted HTTPS requests to the VPN server of an affected device. A successful exploit could allow the attacker to cause the Cisco AnyConnect VPN server to stop accepting new connections, preventing new SSL VPN connections from being established. Existing SSL VPN sessions are not impacted. Note: When the attack traffic stops, the Cisco AnyConnect VPN server recovers gracefully without requiring manual intervention.

A vulnerability in the OLE2 file format parser of ClamAV could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an incorrect check for end-of-string values during scanning, which may result in a heap buffer over-read. An attacker could exploit this vulnerability by submitting a crafted file containing OLE2 content to be scanned by ClamAV on an affected device. A successful exploit could allow the attacker to cause the ClamAV scanning process to terminate, resulting in a DoS condition on the affected software and consuming available system resources. For a description of this vulnerability, see the ClamAV blog .

The REST interface in Cisco Spark 2015-06 allows remote attackers to cause a denial of service (resource outage) by accessing an administrative page, aka Bug ID CSCuv84125.

libclamav in ClamAV (aka Clam AntiVirus), as used in Advanced Malware Protection (AMP) on Cisco Email Security Appliance (ESA) devices before 9.7.0-125 and Web Security Appliance (WSA) devices before 9.0.1-135 and 9.1.x before 9.1.1-041, allows remote attackers to cause a denial of service (AMP process restart) via a crafted document, aka Bug IDs CSCuv78533 and CSCuw60503.

A vulnerability in the TLS processing feature of Cisco Firepower Threat Defense (FTD) Software for Cisco Firepower 2100 Series could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to an issue that occurs when TLS traffic is processed. An attacker could exploit this vulnerability by sending certain TLS traffic over IPv4 through an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition and impacting traffic to and through the affected device.

A vulnerability in the Locator ID Separation Protocol (LISP) feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload. This vulnerability is due to the incorrect handling of LISP packets. An attacker could exploit this vulnerability by sending a crafted LISP packet to an affected device. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition. Note: This vulnerability could be exploited over either IPv4 or IPv6 transport.

Attackers can crash a Cisco IOS router or device, provided they can get to an interactive prompt (such as a login). This applies to some IOS 9.x, 10.x, and 11.x releases.

The Neighbor Discovery (ND) protocol implementation in the IPv6 stack in Cisco IOS XE 2.1 through 3.17S, IOS XR 2.0.0 through 5.3.2, and NX-OS allows remote attackers to cause a denial of service (packet-processing outage) via crafted ND messages, aka Bug ID CSCuz66542, as exploited in the wild in May 2016.

A vulnerability in the Resource Reservation Protocol (RSVP) feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to a buffer overflow when processing crafted RSVP packets. An attacker could exploit this vulnerability by sending RSVP traffic to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Multiple Cisco products are affected by a vulnerability in the rate filtering feature of the Snort detection engine that could allow an unauthenticated, remote attacker to bypass a configured rate limiting filter.  This vulnerability is due to an incorrect connection count comparison. An attacker could exploit this vulnerability by sending traffic through an affected device at a rate that exceeds a configured rate filter. A successful exploit could allow the attacker to successfully bypass the rate filter. This could allow unintended traffic to enter the network protected by the affected device.

A vulnerability in the HTTP Server feature of Cisco IOS XE Software when the Telephony Service feature is enabled could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to a null pointer dereference when accessing specific URLs. An attacker could exploit this vulnerability by sending crafted HTTP traffic to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, causing a DoS condition on the affected device.

A vulnerability in the External Agent Assignment Service (EAAS) feature of Cisco Enterprise Chat and Email (ECE) 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 Media Routing Peripheral Interface Manager (MR PIM) traffic that is received by an affected device. An attacker could exploit this vulnerability by sending crafted MR PIM traffic to an affected device. A successful exploit could allow the attacker to trigger a failure on the MR PIM connection between Cisco ECE and Cisco Unified Contact Center Enterprise (CCE), leading to a DoS condition on EAAS that would prevent customers from starting chat, callback, or delayed callback sessions. Note: When the attack traffic stops, the EAAS process must be manually restarted to restore normal operation. To restart the process in the System Console, choose Shared Resources > Services > Unified CCE > EAAS, then click Start.

emWEB on Cisco Adaptive Security Appliances (ASA) 5500 series devices with software before 8.2(3) allows remote attackers to cause a denial of service (daemon crash) via a request for a document whose name contains space characters, aka Bug ID CSCsy08416.

The HTTPS Proxy feature in Cisco AsyncOS before 8.5.3-051 and 9.x before 9.0.0-485 on Web Security Appliance (WSA) devices allows remote attackers to cause a denial of service (service outage) by leveraging certain intranet connectivity and sending a malformed HTTPS request, aka Bug ID CSCuu24840.

Cisco TelePresence Video Communications Server (VCS) X8.x before X8.7.2 allows remote attackers to cause a denial of service (service disruption) via a crafted URI in a SIP header, aka Bug ID CSCuy43258.

Cisco Prime Network Analysis Module (NAM) before 6.2(1-b) miscalculates IPv6 payload lengths, which allows remote attackers to cause a denial of service (mond process crash and monitoring outage) via crafted IPv6 packets, aka Bug ID CSCuy37324.

The TCP implementation in Cisco Videoscape Distribution Suite for Internet Streaming (VDS-IS) 3.3(0), 3.3(1), 4.0(0), and 4.1(0) does not properly initiate new TCP sessions when a previous session is in a FIN wait state, which allows remote attackers to cause a denial of service (TCP outage) via vectors involving FIN packets, aka Bug ID CSCuy45136.

The Wide Area Application Services (WAAS) Express implementation in Cisco IOS 15.1 through 15.5 allows remote attackers to cause a denial of service (device reload) via a crafted TCP segment, aka Bug ID CSCuq59708.

The web-management GUI implementation on Cisco Small Business SG300 devices 1.4.1.x allows remote attackers to cause a denial of service (HTTPS outage) via crafted HTTPS requests, aka Bug ID CSCuw87174.

Cisco IOS XR through 5.3.2 mishandles Local Packet Transport Services (LPTS) flow-base entries, which allows remote attackers to cause a denial of service (session drop) by making many connection attempts to open TCP ports, aka Bug ID CSCux95576.

The packet-processing microcode in Cisco IOS 15.2(2)EA, 15.2(2)EA1, 15.2(2)EA2, and 15.2(4)EA on Industrial Ethernet 4000 devices and 15.2(2)EB and 15.2(2)EB1 on Industrial Ethernet 5000 devices allows remote attackers to cause a denial of service (packet data corruption) via crafted IPv4 ICMP packets, aka Bug ID CSCuy13431.

Cisco IOS XR 4.2.3, 4.3.0, 4.3.4, and 5.3.1 on ASR 9000 devices allows remote attackers to cause a denial of service (CRC and symbol errors, and interface flap) via crafted bit patterns in packets, aka Bug ID CSCuv78548.

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.

Cisco ONS 15454 controller cards with software 9.6 and earlier allow remote attackers to cause a denial of service (card reset) via a TCP FIN attack that triggers file-descriptor exhaustion and a failure to open a CAL pipe, aka Bug ID CSCug97348.

The Active Directory (AD) integration component in Cisco Identity Service Engine (ISE) before 1.2.0.899 patch 7, when AD group-membership authorization is enabled, allows remote attackers to cause a denial of service (authentication outage) via a crafted Password Authentication Protocol (PAP) authentication request, aka Bug ID CSCun25815.

Linux kernel versions 4.9+ can be forced to make very expensive calls to tcp_collapse_ofo_queue() and tcp_prune_ofo_queue() for every incoming packet which can lead to a denial of service.

Cisco IOS 11.x and 12.x allows remote attackers to cause a denial of service by sending the ENVIRON option to the Telnet daemon before it is ready to accept it, which causes the system to reboot.

A denial-of-service issue in Cisco Unified IP Conference Station 7937G 1-4-4-0 through 1-4-5-7 allows attackers to remotely disable the device until it is power cycled. Note: We cannot prove this vulnerability exists. Out of an abundance of caution, this CVE is being assigned to better serve our customers and ensure all who are still running this product understand that the product is end of life and should be removed or upgraded. For more information on this, and how to upgrade, refer to the CVE’s reference information

Multiple vulnerabilities in the Server Message Block Version 2 (SMB2) processor of the Snort detection engine on multiple Cisco products could allow an unauthenticated, remote attacker to bypass the configured policies or cause a denial of service (DoS) condition on an affected device. These vulnerabilities are due to improper management of system resources when the Snort detection engine is processing SMB2 traffic. An attacker could exploit these vulnerabilities by sending a high rate of certain types of SMB2 packets through an affected device. A successful exploit could allow the attacker to trigger a reload of the Snort process, resulting in a DoS condition. Note: When the snort preserve-connection option is enabled for the Snort detection engine, a successful exploit could also allow the attacker to bypass the configured policies and deliver a malicious payload to the protected network. The snort preserve-connection setting is enabled by default. See the Details ["#details"] section of this advisory for more information. Note: Only products that have Snort 3 configured are affected. Products that are configured with Snort 2 are not affected.

Multiple Cisco products are affected by a vulnerability in Snort rules that 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 Block with Reset or Interactive Block with Reset actions if a rule is configured without proper constraints. An attacker could exploit this vulnerability by sending a crafted IP packet to the affected device. A successful exploit could allow the attacker to cause through traffic to be dropped. Note: Only products with Snort3 configured and either a rule with Block with Reset or Interactive Block with Reset actions configured are vulnerable. Products configured with Snort2 are not vulnerable.

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 IOS XR 3.4.0 through 3.9.1, when BGP is enabled, does not properly handle unrecognized transitive attributes, which allows remote attackers to cause a denial of service (peering reset) via a crafted prefix announcement, as demonstrated in the wild in August 2010 with attribute type code 99, aka Bug ID CSCti62211.

The DHCPv4 server in Cisco IOS XR 5.2.2 on ASR 9000 devices allows remote attackers to cause a denial of service (service outage) via a flood of crafted DHCP packets, aka Bug ID CSCup67822.

The IKEv1 state machine in Cisco IOS 15.4 through 15.6 and IOS XE 3.15 through 3.17 allows remote attackers to cause a denial of service (IPsec connection termination) via a crafted IKEv1 packet to a tunnel endpoint, aka Bug ID CSCuw08236.

Cisco ASR 5000 devices with software 16.0(900) allow remote attackers to cause a denial of service (telnetd process restart) via a TELNET connection, aka Bug ID CSCuv25815.

node-jose is a JavaScript implementation of the JSON Object Signing and Encryption (JOSE) for web browsers and node.js-based servers. Prior to version 2.2.0, when using the non-default "fallback" crypto back-end, ECC operations in `node-jose` can trigger a Denial-of-Service (DoS) condition, due to a possible infinite loop in an internal calculation. For some ECC operations, this condition is triggered randomly; for others, it can be triggered by malicious input. The issue has been patched in version 2.2.0. Since this issue is only present in the "fallback" crypto implementation, it can be avoided by ensuring that either WebCrypto or the Node `crypto` module is available in the JS environment where `node-jose` is being run.

Cisco Content Security Management Appliance (SMA) 7.8.0-000 does not properly validate credentials, which allows remote attackers to cause a denial of service (rapid log-file rollover and application fault) via crafted HTTP requests, aka Bug ID CSCuw09620.

The DHCPv6 server in Cisco IOS on ASR 9000 devices with software 5.2.0 Base allows remote attackers to cause a denial of service (process reset) via crafted packets, aka Bug ID CSCun72171.

The DHCPv6 server in Cisco IOS on ASR 9000 devices with software 5.2.0 Base allows remote attackers to cause a denial of service (process reset) via crafted packets, aka Bug ID CSCun36525.

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.

Cisco Web Security Appliance (WSA) 8.0.6-078 and 8.0.6-115 allows remote attackers to cause a denial of service (service outage) via a flood of TCP traffic that leads to DNS resolution delays, aka Bug IDs CSCur32005 and CSCur07907.

Cisco Prime Infrastructure 2.2 allows remote attackers to cause a denial of service (daemon hang) by sending many SSL renegotiation requests, aka Bug ID CSCuv56830.

Cisco TelePresence Video Communication Server (VCS) Expressway X8.5.2 allows remote attackers to cause a denial of service via invalid variables in a GET request, aka Bug ID CSCuv40528.

Multiple vulnerabilities in the Cisco ATA 190 Series Analog Telephone Adapter Software could allow an attacker to perform a command injection attack resulting in remote code execution or cause a denial of service (DoS) condition on an affected device. For more information about these vulnerabilities, see the Details section of this advisory.

A vulnerability in the TCP Normalizer of Cisco Adaptive Security Appliance (ASA) Software and Firepower Threat Defense (FTD) Software operating in transparent mode could allow an unauthenticated, remote attacker to poison MAC address tables, resulting in a denial of service (DoS) vulnerability. This vulnerability is due to incorrect handling of certain TCP segments when the affected device is operating in transparent mode. An attacker could exploit this vulnerability by sending a crafted TCP segment through an affected device. A successful exploit could allow the attacker to poison the MAC address tables in adjacent devices, resulting in network disruption.

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.