vulnerability
Cisco IOS-XR: CVE-2024-20406: Cisco IOS XR Software Segment Routing for Intermediate System-to-Intermediate System Denial of Service Vulnerability
Severity | CVSS | Published | Added | Modified |
---|---|---|---|---|
6 | (AV:A/AC:L/Au:N/C:N/I:N/A:C) | Sep 11, 2024 | Sep 12, 2024 | Jun 23, 2025 |
Description
A vulnerability in the segment routing feature for the Intermediate System-to-Intermediate System (IS-IS) protocol of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to cause a denial of service (DoS) condition on an affected device.
This vulnerability is due to insufficient input validation of ingress IS-IS packets. An attacker could exploit this vulnerability by sending specific IS-IS packets to an affected device after forming an adjacency. A successful exploit could allow the attacker to cause the IS-IS process on all affected devices that are participating in the Flexible Algorithm to crash and restart, resulting in a 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. This vulnerability affects segment routing for IS-IS over IPv4 and IPv6 control planes as well as devices that are configured as level 1, level 2, or multi-level routing IS-IS type.
Solution

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