A flaw in the IPv4 packet‐processing path of Cisco IOS XR Software allows a remote, unauthenticated attacker to send specially crafted IPv4 packets to an affected line card interface. The incorrect handling of these packets can trigger a network processor error that forces the line card to reset or enter a persistent shutdown state. This resultin traffic loss on the affected interface and, if repeated, may require a manual reload to restore normal operation. The weakness is a classic input validation flaw (CWE‑20).

The vulnerability applies to Cisco IOS XR Software running on the ASR 9000 and 9900 Series Aggregation Services Routers as well as the ASR 9902 and 9903 Compact High‑Performance Routers.

The CVSS score of 7.5 indicates a high risk level, but the EPSS score is not available and the vulnerability is not listed in the CISA KEV catalogue. The attack vector is remote and does not require authentication; crafted packets can be injected over the network interface, and transit traffic does not trigger the issue. Successful exploitation leads to a denial of service at the line card level, but it does not directly expose user data or compromise the router’s control plane beyond the reset. The overall exploitation likelihood is moderate, but the impact on network availability is significant if the affected routers support critical traffic flows.