A vulnerability in the Extensible Messaging Client Protocol (XMCP), also referred to as the External Client protocol, of 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 improper handling of malformed XMCP packets. An attacker could exploit this vulnerability by sending a malformed XMCP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload unexpectedly, resulting in a DoS condition. The attacker does not need the XMCP client username to exploit this vulnerability.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20273 are related to improper input validation issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-20.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20272 are related to issues with improper neutralization of special elements that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-74.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20271 are related to insufficient control flow management issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-691.  

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20270 are related to incorrect calculation issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-682.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20269 are related to issues with improper control of a resource through its lifetime that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-664.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20268 are related to issues with improper restriction of operations within the bounds of a memory buffer that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-119.

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20267 are related to improper access control issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-284. 

A vulnerability in the Blocks Extensible Exchange Protocol (BEEP) feature of 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 improper handling when parsing a specific BEEP SOAP request. An attacker could exploit this vulnerability by sending a specific BEEP SOAP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition.

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. This vulnerability is due to improper error handling when parsing SNMP requests. This vulnerability affects all versions of SNMP — Versions 1, 2c, and 3. An attacker could exploit this vulnerability by sending a malformed SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly. The attacker must have the SNMPv1 or v2c read-only or read-write community string or valid SNMPv3 user credentials on the affected device.

A vulnerability in the bootloader of Cisco IOS XE Software for Cisco Catalyst 9200 Series Switches, Cisco Catalyst ESS9300 Embedded Series Switches, Cisco Catalyst IE9310 and IE9320 Rugged Series Switches, and Cisco IE3500 and IE3505 Rugged Series Switches could allow an authenticated, local attacker with level-15 privileges or an unauthenticated attacker with physical access to an affected device to execute arbitrary code at boot time and break the chain of trust. This vulnerability is due to insufficient validation of software at boot time. An attacker could exploit this vulnerability by manipulating the loaded binaries on an affected device to bypass some of the integrity checks that are performed during the boot process. A successful exploit could allow the attacker to execute code that bypasses the requirement to run Cisco-signed images. Cisco has assigned this security advisory a Security Impact Rating (SIR) of High rather than Medium as the score indicates because this vulnerability allows an attacker to bypass a major security feature of a device.

A vulnerability in the TLS library of Cisco IOS XE Software could allow an unauthenticated, adjacent attacker to exhaust the available memory of an affected device. This vulnerability is due to improper management of memory resources during TLS connection setup. An attacker could exploit this vulnerability by repeatedly triggering the conditions that cause the memory increase. This could be done in a variety of ways, such as by repeatedly attempting Extensible Authentication Protocol (EAP) authentication when local EAP is enabled on an affected device or by using a machine-in-the-middle attack and resetting TLS connections between the affected device and other devices. A successful exploit could allow the attacker to exhaust the available memory on an affected device, resulting in an unexpected reload and a denial of service (DoS) condition.

A vulnerability in the Internet Key Exchange version 2 (IKEv2) feature of Cisco IOS Software, Cisco IOS XE Software, Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to trigger a memory leak, resulting in a denial of service (DoS) condition on an affected device. This vulnerability is due to improper parsing of IKEv2 packets. An attacker could exploit this vulnerability by sending crafted IKEv2 packets to an affected device. A successful exploit of Cisco IOS Software and IOS XE Software could allow the attacker to cause the affected device to reload, resulting in a DoS condition. A successful exploit of Cisco Secure Firewall ASA Software and Secure FTD Software could allow the attacker to partially exhaust system memory, resulting in system instability, such as the inability to establish new IKEv2 VPN sessions. A manual reboot of the device is required to recover from this condition.

A vulnerability in the DHCP snooping feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause BOOTP packets to be forwarded between VLANs, resulting in a denial of service (DoS) condition. This vulnerability is due to improper handling of BOOTP packets on Cisco Catalyst 9000 Series Switches. An attacker could exploit this vulnerability by sending BOOTP request packets to an affected device. A successful exploit could allow an attacker to forward BOOTP packets from one VLAN to another, resulting in BOOTP VLAN leakage and potentially leading to high CPU utilization. This makes the device unreachable (either through console or remote management) and unable to forward traffic, resulting in a DoS condition. Note: This vulnerability can be exploited with either unicast or broadcast BOOTP packets. There are workarounds that address this vulnerability.

A vulnerability in the web services of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software, Cisco Secure Firewall Threat Defense (FTD) Software, Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an unauthenticated, remote attacker (Cisco ASA and FTD Software) or authenticated, remote attacker (Cisco IOS, IOS XE, and IOS XR Software) with low user privileges to execute arbitrary code on an affected device. This vulnerability is due to improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by sending crafted HTTP requests to a targeted web service on an affected device after obtaining additional information about the system, overcoming exploit mitigations, or both. A successful exploit could allow the attacker to execute arbitrary code as root, which may lead to the complete compromise of the affected device. For more information about this vulnerability, see the Details ["#details"] section of this advisory.

A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker with administrative privileges to execute arbitrary commands as root on the underlying operating system of an affected device. This vulnerability is due to insufficient validation of user arguments that are passed to specific CLI commands. An attacker could exploit this vulnerability by logging in to the device CLI with valid administrative (level 15) credentials and using crafted commands at the CLI prompt. A successful exploit could allow the attacker to execute arbitrary commands as root.

A vulnerability in the CLI of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, local 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. An attacker with a low-privileged account could exploit this vulnerability by using crafted commands at the CLI prompt. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition.

Multiple vulnerabilities in Cisco IOS XE Software of could allow an authenticated, local attacker with level-15 privileges or an unauthenticated attacker with physical access to the device to execute persistent code at boot time and break the chain of trust. These vulnerabilities are due path traversal and improper image integrity validation. A successful exploit could allow the attacker to execute persistent code on the underlying operating system. Because this allows the attacker to bypass a major security feature of the device, Cisco has raised the Security Impact Rating (SIR) of this advisory from Medium to High. For more information about these vulnerabilities, see the Details ["#details"] section of this advisory. ERP

A vulnerability in the handling of certain Ethernet frames in Cisco IOS XE Software for Catalyst 9000 Series Switches could allow an unauthenticated, adjacent attacker to cause an egress port to become blocked and drop all outbound traffic. This vulnerability is due to improper handling of crafted Ethernet frames. An attacker could exploit this vulnerability by sending crafted Ethernet frames through an affected switch. A successful exploit could allow the attacker to cause the egress port to which the crafted frame is forwarded to start dropping all frames, resulting in a denial of service (DoS) condition.

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS XE Software could allow an authenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper error handling when parsing a specific SNMP request. An attacker could exploit this vulnerability by sending a specific SNMP request to an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition. This vulnerability affects SNMP versions 1, 2c, and 3. To exploit this vulnerability through SNMPv2c or earlier, the attacker must know a valid read-write or read-only SNMP community string for the affected system. To exploit this vulnerability through SNMPv3, the attacker must have valid SNMP user credentials for the affected system.

A vulnerability in the Simple Network Management Protocol (SNMP) subsystem of Cisco IOS Software and Cisco IOS XE Software could allow the following: An authenticated, remote attacker with low privileges could cause a denial of service (DoS) condition on an affected device that is running Cisco IOS Software or Cisco IOS XE Software. To cause the DoS, the attacker must have the SNMPv2c or earlier read-only community string or valid SNMPv3 user credentials. An authenticated, remote attacker with high privileges could execute code as the root user on an affected device that is running Cisco IOS XE Software. To execute code as the root user, the attacker must have the SNMPv1 or v2c read-only community string or valid SNMPv3 user credentials and administrative or privilege 15 credentials on the affected device. An attacker could exploit this vulnerability by sending a crafted SNMP packet to an affected device over IPv4 or IPv6 networks. This vulnerability is due to a stack overflow condition in the SNMP subsystem of the affected software. A successful exploit could allow a low-privileged attacker to cause the affected system to reload, resulting in a DoS condition, or allow a high-privileged attacker to execute arbitrary code as the root user and obtain full control of the affected system. Note: This vulnerability affects all versions of SNMP.

A vulnerability in the implementation of the TACACS+ protocol in Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to view sensitive data or bypass authentication. This vulnerability exists because the system does not properly check whether the required TACACS+ shared secret is configured. A machine-in-the-middle attacker could exploit this vulnerability by intercepting and reading unencrypted TACACS+ messages or impersonating the TACACS+ server and falsely accepting arbitrary authentication requests. A successful exploit could allow the attacker to view sensitive information in a TACACS+ message or bypass authentication and gain access to the affected device.

A vulnerability in the Network-Based Application Recognition (NBAR) feature of Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, causing a denial of service (DoS) condition. This vulnerability is due to improper handling of malformed Control and Provisioning of Wireless Access Points (CAPWAP) packets. An attacker could exploit this vulnerability by sending malformed CAPWAP packets through an affected device. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition.

A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an unauthenticated, remote attacker to perform a CSRF attack and execute commands on the CLI of an affected device. This vulnerability is due to insufficient CSRF protections for the web-based management interface of an affected device. An attacker could exploit this vulnerability by persuading an already authenticated user to follow a crafted link. A successful exploit could allow the attacker to clear the syslog, parser, and licensing logs on the affected device if the targeted user has privileges to clear those logs.

A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, low-privileged, remote attacker to perform an injection attack against an affected device. This vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by sending crafted input to the web-based management interface. A successful exploit could allow the attacker to read limited files from the underlying operating system or clear the syslog and licensing logs on the affected device.

A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, low-privileged, remote attacker to perform an injection attack against an affected device.r This vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by sending crafted input to the web-based management interface. A successful exploit could allow the attacker to read files from the underlying operating system.

A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker with privilege level 15 to elevate privileges to root on the underlying operating system of an affected device. This vulnerability is due to insufficient input validation when processing specific configuration commands. An attacker could exploit this vulnerability by including crafted input in specific configuration commands. A successful exploit could allow the attacker to elevate privileges to root on the underlying operating system of an affected device. The security impact rating (SIR) of this advisory has been raised to High because an attacker could gain access to the underlying operating system of the affected device and perform potentially undetected actions. Note: The attacker must have privileges to enter configuration mode on the affected device. This is usually referred to as privilege level 15.

A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker with privilege level 15 to elevate privileges to root on the underlying operating system of an affected device. This vulnerability is due to insufficient input validation when processing specific configuration commands. An attacker could exploit this vulnerability by including crafted input in specific configuration commands. A successful exploit could allow the attacker to elevate privileges to root on the underlying operating system of an affected device. The security impact rating (SIR) of this advisory has been raised to High because an attacker could gain access to the underlying operating system of the affected device and perform potentially undetected actions. Note: The attacker must have privileges to enter configuration mode on the affected device. This is usually referred to as privilege level 15.

A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker with privilege level 15 to elevate privileges to root on the underlying operating system of an affected device. This vulnerability is due to insufficient input validation when processing specific configuration commands. An attacker could exploit this vulnerability by including crafted input in specific configuration commands. A successful exploit could allow the attacker to elevate privileges to root on the underlying operating system of an affected device. The security impact rating (SIR) of this advisory has been raised to High because an attacker could gain access to the underlying operating system of the affected device and perform potentially undetected actions. Note: The attacker must have privileges to enter configuration mode on the affected device. This is usually referred to as privilege level 15.