CVE-2025-39925

A flaw was discovered in the J1939 protocol implementation in the Linux kernel. The NETDEV_UNREGISTER notification handler was missing for undoing changes performed by j1939_sk_bind(). As a result, an extra reference remains on the j1939_priv structure when unregistering a network device, preventing its usage count from dropping and thus blocking the unregister_netdevice() call

This vulnerability is rated as having a Moderate impact for Red Hat Enterprise Linux because exploitation is restricted to local environments and results primarily in a denial of service. The Controller Area Network (CAN) J1939 protocol is not utilized in typical server or workstation deployments, requiring specific automotive or industrial networking hardware or virtual interfaces. To trigger the flaw, an attacker must interact with bound J1939 network sockets while a network interface is being dismantled, causing kernel execution to stall during device unregistration.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.