CVE-2025-20142 Cisco IOS XR Software for ASR 9000 Series Routers L2VPN Denial of Service Vulnerability

High 8.6 Published 12 Mar 2025 Updated 21 Mar 2025

Remote attackers can cause line card resets and traffic loss on Cisco ASR routers by sending malformed IPv4 packets to interfaces with ACLs or QoS policies.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2025-20142?

CVE-2025-20142 is a high-severity denial of service vulnerability in Cisco Ios Xr, published on 12 Mar 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A vulnerability in the IPv4 access control list (ACL) feature and quality of service (QoS) policy 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 packets that are received on line cards where the interface has either an IPv4 ACL or QoS policy applied. An attacker could exploit this vulnerability by sending crafted IPv4 packets through an affected device. A successful exploit could allow the attacker to cause network processor errors, resulting in a reset or shutdown of the network process. Traffic over that line card would be lost while the line card reloads. Note: This vulnerability has predominantly been observed in Layer 2 VPN (L2VPN) environments where an IPv4 ACL or QoS policy has been applied to the bridge virtual interface. Layer 3 configurations where the interface has either an IPv4 ACL or QoS policy applied are also affected, though the vulnerability has not been observed.

Weakness: CWE-20

Which versions are affected by CVE-2025-20142?

It affects 1 product.

Products include Cisco Ios Xr.

How do I fix CVE-2025-20142?

No fix has been published for CVE-2025-20142 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-2025-20142 being exploited?

There is no known exploitation of CVE-2025-20142 in the wild and no public exploit code.

All Cisco Ios Xr vulnerabilities

Sources

Also known as GHSA-w9ff-5p26-w67v.