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-2026-20271 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-2026-20269 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-2026-20270 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-2026-20268 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.
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 web UI feature of Cisco IOS XE Software could allow an authenticated, remote attacker to inject commands with the privileges of root. This vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by sending crafted input to the web UI. A successful exploit could allow the attacker to inject commands to the underlying operating system with root privileges.
A vulnerability in the SSH implementation of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload. This vulnerability is due to improper handling of resources during an exceptional situation. An attacker could exploit this vulnerability by continuously connecting to an affected device and sending specific SSH requests. A successful exploit could allow the attacker to cause the affected device to reload.
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.
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 IPv6 traffic processing of Cisco IOS XE Wireless Controller Software for Cisco Catalyst 9000 Family Wireless Controllers could allow an unauthenticated, adjacent attacker to cause a Layer 2 (L2) loop in a configured VLAN, resulting in a denial of service (DoS) condition for that VLAN. The vulnerability is due to a logic error when processing specific link-local IPv6 traffic. An attacker could exploit this vulnerability by sending a crafted IPv6 packet that would flow inbound through the wired interface of an affected device. A successful exploit could allow the attacker to cause traffic drops in the affected VLAN, thus triggering the DoS condition.
A vulnerability in the Internet Key Exchange Version 2 (IKEv2) support for the AutoReconnect feature of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, remote attacker to exhaust the free IP addresses from the assigned local pool. This vulnerability occurs because the code does not release the allocated IP address under certain failure conditions. An attacker could exploit this vulnerability by trying to connect to the device with a non-AnyConnect client. A successful exploit could allow the attacker to exhaust the IP addresses from the assigned local pool, which prevents users from logging in and leads to a denial of service (DoS) condition.
A vulnerability in Cisco IOS XE Software for Cisco Catalyst 3650 and Catalyst 3850 Series Switches 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 improper resource management when processing traffic that is received on the management interface. An attacker could exploit this vulnerability by sending a high rate of traffic to the management interface. A successful exploit could allow the attacker to cause the device to reload, resulting in a DoS condition.
A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker to gain shell access on an affected device and execute commands on the underlying operating system (OS). The vulnerability is due to insufficient enforcement of the consent token in authorizing shell access. An attacker could exploit this vulnerability by authenticating to the CLI and requesting shell access on an affected device. A successful exploit could allow the attacker to gain shell access on the affected device and execute commands on the underlying OS.
A vulnerability in the Guest Shell of Cisco IOS XE Software could allow an authenticated, local attacker to perform directory traversal on the base Linux operating system of Cisco IOS XE Software. The vulnerability is due to incomplete validation of certain commands. An attacker could exploit this vulnerability by first accessing the Guest Shell and then entering specific commands. A successful exploit could allow the attacker to execute arbitrary code on the base Linux operating system.
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 transient SIP packets on which NAT is performed on an affected device. An attacker could exploit this vulnerability by using UDP port 5060 to send crafted SIP packets 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.
A vulnerability in the TrustSec CLI parser of Cisco IOS and Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload. This vulnerability is due to an improper interaction between the web UI and the CLI parser. An attacker could exploit this vulnerability by requesting a particular CLI command to be run through the web UI. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition.
A vulnerability in the locally significant certificate (LSC) provisioning feature of Cisco Catalyst 9800 Series Wireless Controllers that are running Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause a memory leak that could lead to a denial of service (DoS) condition. The vulnerability is due to incorrect processing of certain public key infrastructure (PKI) packets. An attacker could exploit this vulnerability by sending crafted Secure Sockets Layer (SSL) packets to an affected device. A successful exploit could cause an affected device to continuously consume memory, which could result in a memory allocation failure that leads to a crash and causes a DoS condition.
A vulnerability in the Tool Command Language (Tcl) interpreter of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, local attacker with privileged EXEC credentials to execute arbitrary code on the underlying operating system (OS) with root privileges. The vulnerability is due to insufficient input validation of data passed to the Tcl interpreter. An attacker could exploit this vulnerability by loading malicious Tcl code on an affected device. A successful exploit could allow the attacker to cause memory corruption or execute the code with root privileges on the underlying OS of the affected device.
A vulnerability in the processing of boot options of specific Cisco IOS XE Software switches could allow an authenticated, local attacker with root shell access to the underlying operating system (OS) to conduct a command injection attack during device boot. This vulnerability is due to insufficient input validation checks while processing boot options. An attacker could exploit this vulnerability by modifying device boot options to execute attacker-provided code. A successful exploit may allow an attacker to bypass the Secure Boot process and execute malicious code on an affected device with root-level privileges.
A vulnerability in software image verification in Cisco IOS XE Software could allow an unauthenticated, physical attacker to install and boot a malicious software image or execute unsigned binaries on an affected device. The vulnerability is due to an improper check on the area of code that manages the verification of the digital signatures of system image files during the initial boot process. An attacker could exploit this vulnerability by loading unsigned software on an affected device. A successful exploit could allow the attacker to install and boot a malicious software image or execute unsigned binaries on the targeted device.
A vulnerability in the ROMMON of Cisco IOS XE Software could allow an authenticated, local attacker to elevate privileges to those of the root user of the underlying operating system. The vulnerability is due to the ROMMON allowing for special parameters to be passed to the device at initial boot up. An attacker could exploit this vulnerability by sending parameters to the device at initial boot up. An exploit could allow the attacker to elevate from a Priv15 user to the root user and execute arbitrary commands with the privileges of the root user.
A vulnerability in Cisco IOS XE Software could allow an authenticated, local attacker to escalate their privileges to a user with root-level privileges. The vulnerability is due to insufficient validation of user-supplied content. This vulnerability could allow an attacker to load malicious software onto an affected device.
A vulnerability in the Virtual Services Container of Cisco IOS XE Software could allow an authenticated, local attacker to gain root-level privileges on an affected device. The vulnerability is due to insufficient validation of a user-supplied open virtual appliance (OVA). An attacker could exploit this vulnerability by installing a malicious OVA on an affected device.
A vulnerability in the hardware crypto driver of Cisco IOS XE Software for Cisco 4300 Series Integrated Services Routers and Cisco Catalyst 9800-L Wireless Controllers could allow an unauthenticated, remote attacker to disconnect legitimate IPsec VPN sessions to an affected device. The vulnerability is due to insufficient verification of authenticity of received Encapsulating Security Payload (ESP) packets. An attacker could exploit this vulnerability by tampering with ESP cleartext values as a man-in-the-middle.
A vulnerability in the Flexible NetFlow Version 9 packet processor of Cisco IOS XE Software for Cisco Catalyst 9800 Series Wireless Controllers could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper validation of parameters in a Flexible NetFlow Version 9 record. An attacker could exploit this vulnerability by sending a malformed Flexible NetFlow Version 9 packet to the Control and Provisioning of Wireless Access Points (CAPWAP) data port of an affected device. An exploit could allow the attacker to trigger an infinite loop, resulting in a process crash that would cause a reload of the device.
Multiple vulnerabilities in the implementation of the Common Industrial Protocol (CIP) feature of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to cause an affected device to reload, resulting in a denial of service (DoS) condition. The vulnerabilities are due to insufficient input processing of CIP traffic. An attacker could exploit these vulnerabilities by sending crafted CIP traffic to be processed by 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 Session Initiation Protocol (SIP) library of Cisco IOS Software and Cisco IOS XE Software could allow an unauthenticated, remote attacker to trigger a reload of an affected device, resulting in a denial of service (DoS) condition. The vulnerability is due to insufficient sanity checks on received SIP messages. An attacker could exploit this vulnerability by sending crafted SIP messages to an affected device. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a denial of service condition.