A vulnerability in the Linux kernel AF_IUCV transport layer allows adjacent network attackers to inject data into existing sockets or cause denial of service conditions.

The function afiucv_hs_rcv improperly validates the ingress network device when matching incoming frames against AF_IUCV sockets. This allows an unauthenticated attacker on the same HiperSockets segment to misroute frames, leading to data injection into established connections, socket hijacking, or denial of service via accept-queue exhaustion.

The vulnerability carries a CVSS score of 8.1, reflecting its potential for high impact on data integrity and service availability. Successful exploitation could result in the compromise of sensitive data transmitted over IUCV connections or the sudden disruption of critical system services, leading to operational downtime and potential loss of communication between trusted guest systems.

Immediate Action: Update the Linux kernel to version 6.12.109, 6.18.50, 7.2.4, or later, as provided by your distribution vendor.

Proactive Monitoring: Monitor system logs for unexpected AF_IUCV socket errors or unusual network traffic patterns originating from the HiperSockets segment.

Compensating Controls: Restrict access to the HiperSockets segment to authorized systems only, as the vulnerability relies on the attacker having local network adjacency.

Public Exploit Available: Unknown

Given the high severity of this vulnerability, organizations operating Linux kernels in mainframe or virtualization environments should prioritize patching. Apply the recommended kernel updates as soon as they become available through your distribution channels to mitigate the risk of unauthorized data injection or service disruption.