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CVE-2025-20146

HIGHCVSS 8.6/10EPSS 0.50%

Last modified

CVE-2025-20146 is a high-severity vulnerability rated 8.6/10 on the CVSS scale. 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. EPSS estimates a 0.50% chance of exploitation in the next 30 days.

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 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.

Metrics

CVSS 3.1
8.6/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H

EPSS Probability
0.50%

38.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
CiscoIos Xr7.9.21
CiscoIos Xr7.10.2
CiscoIos Xr7.11.1
CiscoIos Xr7.11.2
CiscoIos Xr7.11.21
CiscoIos Xr24.1.1
CiscoIos Xr24.1.2
CiscoIos Xr24.2.1
CiscoIos Xr24.2.2
CiscoIos Xr24.3.1
CiscoIos Xr24.3.2

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2025-20146?
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.
How severe is CVE-2025-20146?
CVE-2025-20146 has a CVSS score of 8.6/10 (HIGH severity). The EPSS model estimates a 0.50% probability of exploitation in the next 30 days.
How do I fix CVE-2025-20146?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-20146?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST