CVE-2025-20146High· 8.6▾ TwilightA 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 unaut…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 47.3 · likelihood 0.1 · exploitation 0
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Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CSAF
0.5%
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.
Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. There are mitigations that address this vulnerability.
This advisory is part of the March 2025 release of the Cisco IOS XR Software Security Advisory Bundled Publication. For a complete list of the advisories and links to them, see Cisco Event Response: March 2025 Semiannual Cisco IOS XR Software Security Advisory Bundled Publication ["https://sec.cloudapps.cisco.com/security/center/viewErp.x?alertId=ERP-75548"].
Cisco IOS XR Software for ASR 9000 Series Routers Layer 3 Multicast Denial of Service Vulnerability. Released 2025-03-12.
Affected:
Cisco has released software updates that address this vulnerability. https://software.cisco.com
Connected by shared product, vendor, weakness, or advisory.
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