CVE-2025-20189 Denial of service in Cisco IOS XE Software

High 7.4 Published 7 May 2025 Updated 7 May 2025

An unauthenticated adjacent attacker can cause a router reload by sending crafted ARP messages, leading to a denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2025-20189?

CVE-2025-20189 is a high-severity denial of service vulnerability in Cisco Ios Xe, published on 7 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

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.

Weakness: CWE-762

Which versions are affected by CVE-2025-20189?

It affects 1 product.

Products include Cisco Ios Xe.

How do I fix CVE-2025-20189?

No fix has been published for CVE-2025-20189 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2025-20189 being exploited?

There is no known exploitation of CVE-2025-20189 in the wild and no public exploit code.

All Cisco Ios Xe vulnerabilities

Sources

Also known as GHSA-v76p-4wxx-wrpq.