CVE-2025-20340 HIGH

CVE-2025-20340: Cisco IOS XR Address Resolution Protocol Broadcast Storm Vulnerability

Vendor Cisco
Product Cisco IOS XR Software
Weakness CWE-400
Published September 10, 2025
Last update September 10, 2025

CVSS base score

7.4/10
Attack vector Adjacent
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

What the vulnerability does

01Description

A vulnerability in the Address Resolution Protocol (ARP) implementation of Cisco IOS XR Software could allow an unauthenticated, adjacent attacker to trigger a broadcast storm, leading to a denial of service (DoS) condition on an affected device.  This vulnerability is due to how Cisco IOS XR Software processes a high, sustained rate of ARP traffic hitting the management interface. Under certain conditions, an attacker could exploit this vulnerability by sending an excessive amount of traffic to the management interface of an affected device, overwhelming its ARP processing capabilities. A successful exploit could result in degraded device performance, loss of management connectivity, and complete unresponsiveness of the system, leading to a DoS condition.

Key dates

02Disclosure timeline

September 10, 2025 CVE published
September 10, 2025 Record updated