CVE-2025-20189: Cisco IOS XE

High severity, CVSS 7.4. EPSS: 0.2% chance of exploitation in the next 30 days.

A vulnerability in the Cisco Express Forwarding functionality of Cisco IOS XE Software for Cisco ASR 903 Aggregation Services Routers with Route Switch Processor 3 (RSP3C) could allow an unauthenticated, adjacent attacker to trigger a denial of service (DoS) condition. This vulnerability is due to improper memory management when Cisco IOS XE Software is processing Address Resolution Protocol (ARP) messages. An attacker could exploit this vulnerability by sending crafted ARP messages at a high rate over a period of time to an affected device. A successful exploit could allow the attacker to exhaust system resources, which eventually triggers a reload of the active route switch processor (RSP). If a redundant RSP is not present, the router reloads.

Affected products

• Cisco IOS XE: version 3.16.0cs only; version 3.16.0s only; version 3.16.1as only; version 3.16.1s only; version 3.16.2as only; version 3.16.2bs only; …

Published 2025-05-07. Last modified 2026-06-17.