Cisco IOS XE Vulnerabilities & Security Advisories
18 advisories tracked · Cisco Security Advisories · 0 listed in the CISA Known Exploited Vulnerabilities catalog
Every row below is a published Cisco advisory that VulniPulse classified as IOS XE, with the CVEs, affected and fixed releases and exploitation status the vendor stated. Severity mix: 1 critical, 8 high, 9 medium.
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Cisco Security Advisories
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Latest Cisco IOS XE advisories
Critical [CVE-2026-20267 +6] Cisco IOS XE Software Security Hardening Release: August 2026
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. These vulnerabilities were found during internal testing and are not known to be actively exploited. To assist customers in patching and streamline the disclosure process, Cisco has grouped these issues by their underlying vulnerability class — Common Weakness Enumeration (CWE) — and assigned a single Common Vulnerabilities and Exposures identifier (CVE ID). Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.
High [CVE-2026-20263] Cisco IOS XE Software Blocks Extensible Exchange Protocol Denial of Service Vulnerability
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. Cisco has released software updates that address this vulnerability. There are no workarounds that address these vulnerabilities.
High [CVE-2026-20124] Cisco IOS XE Software SNMP Denial of Service Vulnerability
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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. There is a mitigation that addresses this vulnerability.
High [CVE-2026-20301] Cisco IOS Software and IOS XE Software Extensible Messaging Client Protocol Denial of Service Vulnerability
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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. There is a mitigation that addresses this vulnerability.
Medium [CVE-2026-20311] Cisco IOS XE Software Web-Based Management Interface Denial of Service Vulnerability
A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, remote attacker with low privileges to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient error handling in the web-based management interface. An attacker could exploit this vulnerability by authenticating with a malformed certificate. A successful exploit could allow the attacker to cause the affected device to reload, resulting in a DoS condition. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
Medium [CVE-2026-20308] Cisco IOS XE Software Web-Based Management Interface Denial of Service Vulnerability
A vulnerability in the web-based management interface of Cisco IOS XE Software could allow an authenticated, remote attacker with low privileges to perform a denial of service (DoS) 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 of an affected device. A successful exploit could allow the attacker to cause the web-based management interface to become unresponsive. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Affected products named by the advisory: Aironet Access Point Software (IOS XE Controller); IOS XE Catalyst SD-WAN; IOS XE Software Bootloader (ROMMON); IOS XG Software; and 1 more.
Medium [CVE-2026-20110] Cisco IOS XE Software Denial of Service Vulnerability
A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected device. This vulnerability exists because incorrect privileges are associated with the start maintenance command. An attacker could exploit this vulnerability by accessing the management CLI of the affected device as a low-privileged user and using the start maintenance command. A successful exploit could allow the attacker to put the device in maintenance mode, which shuts down interfaces, resulting in a denial of service (DoS) condition. In case of exploitation, a device administrator can connect to the CLI and use the stop maintenance command to restore operations. Cisco has released software updates that address this vulnerability. There are workarounds that address this vulnerability. This advisory is part of the March 2026 release of the Cisco IOS and IOS XE Software Security Advisory Bundled Publication.
High [CVE-2026-20004] Cisco IOS XE Software TLS Memory Exhaustion Denial of Service Vulnerability
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 att… Affected products named by the advisory: Cisco IOS XE Software 16.9.2; Cisco IOS XE Software 16.9.1a; Cisco IOS XE Software 16.9.1b; Cisco IOS XE Software 16.9.1s; and 3 more.
High [CVE-2026-20086] Cisco IOS XE Wireless Controller Software for the Catalyst CW9800 Family CAPWAP Denial of Service Vulnerability
A vulnerability in the processing of Control and Provisioning of Wireless Access Points (CAPWAP) packets of Cisco IOS XE Wireless Controller Software for the Catalyst CW9800 Family 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 a malformed CAPWAP packet. An attacker could exploit this vulnerability by sending a malformed CAPWAP packet to an affected device. A successful exploit could allow the attacker to cause the affected device to reload unexpectedly, resulting in a DoS … Affected products named by the advisory: Cisco IOS XE Software 17.14.1; Cisco IOS XE Software 17.15.1; Cisco IOS XE Software 17.15.3; Cisco IOS XE Software 17.15.2b; and 2 more.
High [CVE-2026-20084] Cisco IOS XE Software for Catalyst 9000 Series Switches DHCP Snooping Denial of Service Vulnerability
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 utiliz… Affected products named by the advisory: Cisco IOS XE Software 16.6.1; Cisco IOS XE Software 16.6.2; Cisco IOS XE Software 16.6.3; Cisco IOS XE Software 16.6.5; and 3 more.
High [CVE-2026-20125] Cisco IOS Software and IOS XE Software Release 3E HTTP Server Denial of Service Vulnerability
A vulnerability in the HTTP Server feature of Cisco IOS Software and Cisco IOS XE Software Release 3E could allow an authenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by sending malformed HTTP requests to an affected device. A successful exploit could allow the attacker to cause a watchdog timer to expire and the device to reload, resulting in a DoS condition. Affected products named by the advisory: Cisco IOS 12.2(33)CY1; Cisco IOS 12.2(33)CY2; Cisco IOS 12.2(55)SE3; Cisco IOS 12.2(55)SE2; and 2 more.
High [CVE-2026-20012] Cisco IOS, IOS XE, Secure Firewall Adaptive Security Appliance, and Secure Firewall Threat Defense Software IKEv2 Denial of Service Vulnerability
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 … Affected products named by the advisory: Cisco IOS 15.2(1)S1; Cisco IOS 15.2(4)S; Cisco IOS 15.2(1)S2; Cisco IOS 15.2(2)S1; and 2 more.
Medium [CVE-2026-20083] Cisco IOS XE Software Secure Copy Protocol Server Denial of Service Vulnerability
A vulnerability in the Secure Copy Protocol (SCP) server feature of Cisco IOS XE Software could allow an authenticated, local attacker with low privileges to cause a denial of service (DoS) condition on an affected device. This vulnerability is due to improper handling of a malformed SCP request. An attacker could exploit this vulnerability by issuing a crafted command through SSH. A successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition. Cisco has released software updates that address this vulnerability. There are no workaround… Affected products named by the advisory: Cisco IOS XE Software 3.5.0E; Cisco IOS XE Software 3.5.1E; Cisco IOS XE Software 3.5.2E; Cisco IOS XE Software 3.5.3E; and 4 more.
Medium [CVE-2026-20104] Cisco IOS XE Software for Cisco Catalyst and Rugged Series Switches Secure Boot Bypass Vulnerability
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 … Affected products named by the advisory: Cisco IOS XE Software 16.12.8; Cisco IOS XE Software 16.12.6a; Cisco IOS XE Software 16.12.7; Cisco IOS XE Software 17.3.3; and 3 more.
Medium [CVE-2026-20115] Cisco IOS XE Software Secure Channel for Meraki Information Disclosure Vulnerability
A vulnerability in Cisco IOS XE Software for Cisco Meraki could allow a remote, unauthenticated attacker to view confidential device information. This vulnerability is due to a device configuration upload being performed over an insecure tunnel. An attacker could exploit this vulnerability by conducting an on-path attack between the affected device and the Cisco Meraki Dashboard. A successful exploit could allow the attacker to view sensitive device configuration information. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vuln… Affected products named by the advisory: Cisco IOS XE Software 17.14.1a; Cisco IOS XE Software 17.15.1w; Cisco IOS XE Software 17.15.1a; Cisco IOS XE Software 17.15.2; and 2 more.
Medium [CVE-2026-20113] Cisco IOx Application Hosting Environment Carriage Return Line Feed Injection Vulnerability
A vulnerability in the web-based Cisco IOx application hosting environment management interface of Cisco IOS XE Software could allow an unauthenticated, remote attacker to perform a carriage return line feed (CRLF) injection attack against a user. This vulnerability is due to insufficient validation of user input. An attacker could exploit this vulnerability by sending crafted packets to an affected device. A successful exploit could allow the attacker to arbitrarily inject log entries, manipulate the structure of log files, or obscure legitimate log events. Cisco has released software upda… Affected products named by the advisory: Cisco IOS XE Software 16.6.1; Cisco IOS XE Software 16.6.2; Cisco IOS XE Software 16.6.3; Cisco IOS XE Software 16.6.4s; and 2 more.
Medium [CVE-2026-20112] Cisco IOx Application Hosting Environment Stored Cross-Site Scripting Vulnerability
A vulnerability in the web-based Cisco IOx application hosting environment management interface of Cisco IOS XE Software could allow an authenticated, remote attacker to conduct a stored cross-site scripting (XSS) attack against a user of the web-based management interface of an affected device. This vulnerability is due to insufficient validation of user-supplied input. An attacker could exploit this vulnerability by injecting malicious code into specific pages of the interface. A successful exploit could allow the attacker to execute arbitrary script code in the context of the affected in… Affected products named by the advisory: Cisco IOS XE Software 16.6.1; Cisco IOS XE Software 16.6.2; Cisco IOS XE Software 16.6.3; Cisco IOS XE Software 16.6.4s; and 2 more.
Medium [CVE-2026-20114] Cisco IOS XE Software Lobby Ambassador Privilege Escalation Vulnerability
A vulnerability in the Lobby Ambassador web-based management API of Cisco IOS XE Software could allow an authenticated, remote attacker to elevate their privileges and access management APIs that would not normally be available for Lobby Ambassador users. This vulnerability exists because parameters that are received by an API endpoint are not sufficiently validated. An attacker could exploit this vulnerability by authenticating as a Lobby Ambassador user and sending a crafted HTTP request to an affected device. A successful exploit could allow the attacker to create a new user with privile… Affected products named by the advisory: Cisco IOS XE Software 16.11.1a; Cisco IOS XE Software 16.11.1b; Cisco IOS XE Software 16.11.2; Cisco IOS XE Software 16.11.1s; and 2 more.