Cisco IOS XR up to 24.3.2 Layer 3 Multicast denial of service

Summaryinfo

A vulnerability categorized as problematic has been discovered in Cisco IOS XR up to 24.3.2. The affected element is an unknown function of the component Layer 3 Multicast. The manipulation results in denial of service. This vulnerability is known as CVE-2025-20146. It is possible to launch the attack remotely. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Cisco IOS XR up to 24.3.2. It has been classified as critical. Affected is an unknown functionality of the component Layer 3 Multicast. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. CVE summarizes:

A vulnerability in the Layer 3 multicast 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 multicast packets that are received on line cards where the interface has either an IPv4 access control list (ACL) or a QoS policy applied. An attacker could exploit this vulnerability by sending crafted IPv4 multicast packets through an affected device. A successful exploit could allow the attacker to cause line card exceptions or a hard reset. Traffic over that line card would be lost while the line card reloads.

The advisory is shared for download at sec.cloudapps.cisco.com. This vulnerability is traded as CVE-2025-20146 since 10/10/2024. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 08/01/2025). The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Router Operating System

Vendor

• Cisco

Name

• IOS XR

Version

• 7.9.21
• 7.10.2
• 7.11.1
• 7.11.2
• 7.11.21
• 24.1.1
• 24.1.2
• 24.2.1
• 24.2.2
• 24.3.1
• 24.3.2

License

• commercial

Website

• Vendor: https://www.cisco.com/

CPE 2.3info

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CPE 2.2info

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