CVE-2025-20146
Published: 12 March 2025
Summary
CVE-2025-20146 is a high-severity Improper Input Validation (CWE-20) vulnerability in Cisco Ios Xr. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Network Denial of Service (T1498); ranked in the top 23.5% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SC-5 (Denial-of-service Protection) and SI-10 (Information Input Validation).
Threat & Defense at a Glance
Threat & Defense Details
Mitigating Controls (NIST 800-53 r5)AI
Directly mitigates the vulnerability by requiring timely remediation and patching of the flaw in Cisco IOS XR Software that mishandles malformed IPv4 multicast packets.
Addresses the root cause of CWE-20 improper input validation by enforcing validation mechanisms for IPv4 multicast packets received on affected line cards.
Protects against the DoS condition by limiting the effects of crafted IPv4 multicast packets that trigger line card resets.
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability enables remote unauthenticated exploitation of input validation flaw in network device to cause line card crash/reset and traffic DoS, directly matching Network Denial of Service via device vulnerability exploitation.
NVD Description
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…
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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.
Deeper analysisAI
CVE-2025-20146 is a vulnerability in the Layer 3 multicast feature of Cisco IOS XR Software running on Cisco ASR 9000 Series Aggregation Services Routers, ASR 9902 Compact High-Performance Routers, and ASR 9903 Compact High-Performance Routers. The issue stems from the incorrect handling of malformed IPv4 multicast packets received on line cards where the interface has either an IPv4 access control list (ACL) or a QoS policy applied. It has a CVSS v3.1 base score of 8.6 (AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H) and is associated with CWE-20 (Improper Input Validation).
An unauthenticated, remote attacker could exploit this vulnerability by sending crafted IPv4 multicast packets through an affected device. A successful exploit would trigger line card exceptions or a hard reset, resulting in a denial-of-service (DoS) condition where traffic over that line card is lost during the reload process.
Mitigation details are available in the Cisco Security Advisory at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-multicast-ERMrSvq7. Additional context appears in the APNIC blog post at https://blog.apnic.net/2024/09/02/crafting-endless-as-paths-in-bgp/. The vulnerability was published on 2025-03-12.
Details
- CWE(s)