As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XR Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening releases that address multiple internally discovered vulnerabilities.
The vulnerabilities tracked by CVE-2026-20280 are related to improper checking or handling of exceptional condition issues that are grouped under the Common Weakness Enumeration (CWE) CWE-703.
CVSS Score
8.8
EPSS Score
0.005
Published
2026-09-02
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XR Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening releases that address multiple internally discovered vulnerabilities.
The vulnerabilities tracked by CVE-2026-20274 are related to improper resource control issues that are grouped under the Common Weakness Enumeration (CWE) CWE-664.
CVSS Score
9.8
EPSS Score
0.005
Published
2026-09-02
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XR Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening releases that address multiple internally discovered vulnerabilities.
The vulnerabilities tracked by CVE-2026-20276 are related to insufficient control flow management issues that are grouped under the Common Weakness Enumeration (CWE) CWE-691.
CVSS Score
8.6
EPSS Score
0.005
Published
2026-09-02
A vulnerability in task group assignment for a specific CLI command in Cisco IOS XR Software could allow an authenticated, local attacker to elevate privileges and gain full administrative control of an affected device.
This vulnerability is due to incorrect mapping of a command to task groups within the source code. An attacker with a low-privileged account could exploit this vulnerability by using the CLI command to bypass the task group–based checks. A successful exploit could allow the attacker to elevate privileges and perform actions on an affected device without authorization checks.
CVSS Score
8.8
EPSS Score
0.001
Published
2026-03-11
A vulnerability in the Intermediate System-to-Intermediate System (IS-IS) multi-instance routing feature of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause the IS-IS process to restart unexpectedly.
This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending crafted IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process to restart unexpectedly, resulting in a temporary loss of connectivity to advertised networks and a denial of service (DoS) condition.
Note: The IS-IS protocol is a routing protocol. To exploit this vulnerability, an attacker must be Layer 2-adjacent to the affected device and must have formed an adjacency.
CVSS Score
7.4
EPSS Score
0.002
Published
2026-03-11
A vulnerability in the CLI of Cisco IOS XR Software could allow an authenticated, local attacker 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 with a low-privileged account could exploit this vulnerability by using crafted commands at the prompt. A successful exploit could allow the attacker to elevate privileges to root and execute arbitrary commands on the underlying operating system.
CVSS Score
8.8
EPSS Score
0.002
Published
2026-03-11
A vulnerability in the installation process of Cisco IOS XR Software could allow an authenticated, local attacker to bypass Cisco IOS XR Software image signature verification and load unsigned software on an affected device. To exploit this vulnerability, the attacker must have root-system privileges on the affected device.
This vulnerability is due to incomplete validation of files during the installation of an .iso file. An attacker could exploit this vulnerability by modifying contents of the .iso image and then installing and activating it on the device. A successful exploit could allow the attacker to load an unsigned file as part of the image activation process.
CVSS Score
6.0
EPSS Score
0.001
Published
2025-09-10
A vulnerability in the access control list (ACL) processing in the egress direction of Cisco IOS XR Software could allow an unauthenticated, remote attacker to bypass a configured ACL.
This vulnerability exists because certain packets are handled incorrectly when they are received on an ingress interface on one line card and destined out of an egress interface on another line card where the egress ACL is configured. An attacker could exploit this vulnerability by attempting to send traffic through an affected device. A successful exploit could allow the attacker to bypass an egress ACL on the affected device.
For more information about this vulnerability, see the section of this advisory.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability.
CVSS Score
5.8
EPSS Score
0.004
Published
2025-03-12
A vulnerability in the Layer 3 multicast feature of Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers could allow an unauthenticated, remote attacker to cause a line card to reset, resulting in a denial of service (DoS) condition.
This vulnerability is due to the incorrect handling of malformed IPv4 multicast packets that are received on line cards where the interface has either an IPv4 access control list (ACL) or a QoS policy applied. An attacker could exploit this vulnerability by sending crafted IPv4 multicast packets through an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset. Traffic over that line card would be lost while the line card reloads.
CVSS Score
8.6
EPSS Score
0.005
Published
2025-03-12
A vulnerability in the SNMP subsystem of Cisco IOS Software, Cisco IOS XE Software, and Cisco IOS XR Software could allow an authenticated, remote attacker to cause a DoS condition on an affected device.
This vulnerability is due to improper error handling when parsing SNMP requests. An attacker could exploit this vulnerability by sending a crafted SNMP request to an affected device. For Cisco IOS and IOS XE Software, a successful exploit could allow the attacker to cause the device to reload unexpectedly, resulting in a DoS condition. For Cisco IOS XR Software, a successful exploit could allow the attacker to cause the SNMP process to restart, resulting in an interrupted SNMP response from an affected device. Devices that are running Cisco IOS XR Software will not reload.
This vulnerability affects SNMP versions 1, 2c, and 3. To exploit this vulnerability through SNMP v2c 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 SNMP v3, the attacker must have valid SNMP user credentials for the affected system.
CVSS Score
7.7
EPSS Score
0.008
Published
2025-02-05
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