CVE-2025-20146: Cisco IOS XR Software for ASR 9000 Series Routers Layer 3 Multicast Routing Denial of Service Vulnerability
First published: Wed Mar 12 2025(Updated: )
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.
Credit: psirt@cisco.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Cisco IOS XRv 9000 | ||
| Cisco Aggregation Services Router 900 | ||
| Cisco ASR 9902 Compact High-Performance Router | ||
| Cisco ASR 9903 Compact High-Performance Router |
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2025-20146?
CVE-2025-20146 has been rated as a critical vulnerability, allowing for significant risk of disruption.
How do I fix CVE-2025-20146?
To mitigate CVE-2025-20146, users should update their Cisco IOS XR Software to the latest patched version.
What systems are affected by CVE-2025-20146?
CVE-2025-20146 affects the Cisco ASR 9000 Series Routers, ASR 9902, and ASR 9903 Series Routers running the affected IOS XR Software.
What impact can CVE-2025-20146 have on my network?
Exploitation of CVE-2025-20146 can lead to denial of service, impacting network availability and performance.
Is authentication required to exploit CVE-2025-20146?
No, CVE-2025-20146 can be exploited by an unauthenticated remote attacker.
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- canonical/cisco ios xrv 9000
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- canonical/cisco asr 9902 compact high-performance router
- canonical/cisco asr 9903 compact high-performance router