CVE-2026-98747serial: core: fix NULL pointer dereference in serial_core_unregister_port()

Official description

In the Linux kernel, the following vulnerability has been resolved: serial: core: fix NULL pointer dereference in serial_core_unregister_port() port->port_dev is NULL when no port device is installed: it is cleared on teardown, and never set if registration failed before serial_core_port_device_add(). serial_core_unregister_port() passes it straight to serial_core_get_ctrl_dev(), which dereferences it: KASAN: null-ptr-deref in range [0x0000000000000040-0x0000000000000047] RIP: serial_core_unregister_port Call Trace: serial8250_unregister_port serial8250_remove unbind_store Return early when there is no port device, and read port->port_dev under port_mutex. Also clear port->port_dev on the serial_core_register_port() error path, where the port device has already been removed.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/54abbb862366dcaf1f22f1e968358147b7d0547d
• https://git.kernel.org/stable/c/499485a67fbacf4d9afbdb43522388c64f853428