Linux Kernel Vulnerability in j1939 Protocol by The Linux Foundation

CVE-2025-39925

What is CVE-2025-39925?

A vulnerability exists in the Linux kernel's j1939 protocol that impacts the handling of network devices. When the NETDEV_UNREGISTER notification is not implemented, it leads to an issue where the usage count for the virtual CAN device, vcan0, does not decrement correctly. This happens because the j1939_sk_bind() function retains an extra reference to the structure j1939_priv, preventing the expected release of resources when unregistering the network device. To address this, the NETDEV_UNREGISTER notification handler needs to appropriately manage the reference counting for j1939_priv, enabling a clean unbinding process without resource leaks.

References