CVE-2026-68372: Undefined Security Weakness

In the Linux kernel, the following vulnerability has been resolved:

usb: core: port: Deattach Type-C connector on component unbind

connector_unbind() is the mirror of connector_bind(), but it is missing the symmetric call to typec_deattach() that connector_bind() makes via:

if (port_dev->child) typec_attach(port_dev->connector, &port_dev->child->dev);

When a Thunderbolt dock is unplugged, two teardown paths race:

1. The component framework calls connector_unbind() first, which sets port_dev->connector = NULL without calling typec_deattach(). This leaves port->usb2_dev/port->usb3_dev in struct typec_port pointing at the USB device that is about to be freed.

2. usb_disconnect() then calls typec_deattach(port_dev->connector, ...), but port_dev->connector is already NULL, so the call is a no-op and port->usb2_dev is never cleared.

3. Concurrently, UCSI detects a PD partner-disconnect event and calls typec_unregister_partner(), which reads port->usb2_dev (now a dangling pointer to freed memory) and passes it to typec_partner_unlink_device() -> sysfs_remove_link() -> dev_name() on the freed device, corrupting the typec/UCSI partner state.

This corruption leaves the Thunderbolt tunnel in an inconsistent state on the next dock hot-plug. On affected hardware the dock's I225/igc NIC fails to enumerate: AER fires a slot reset while the igc driver is still initialising ("PCIe link lost"), and the subsequent igc_reset attempt hits igc_rd32 on an already-detached device:

igc 0000:2e:00.0 eth0: PCIe link lost, device now detached igc: Failed to read reg 0x0! WARNING: CPU: 9 PID: 129 at drivers/net/ethernet/intel/igc/igc_main.c:7005 igc_rd32+0xa4/0xc0 [igc] Call Trace: igc_disable_pcie_master+0x16/0xa0 [igc] igc_reset_hw_base+0x14/0x170 [igc] igc_reset+0x63/0x110 [igc] igc_io_slot_reset+0x9e/0xd0 [igc] report_slot_reset+0x5d/0xc0 pcie_do_recovery+0x209/0x400 aer_isr_one_error_type+0x235/0x430 aer_isr+0x4e/0x80 irq_thread+0xf4/0x1f0

4. UCSI later handles the PD partner-disconnect and calls typec_unregister_partner(), which still sees the stale port->usb2_dev and tries to remove its sysfs link a second time:

kernfs: can not remove 'typec', no directory WARNING: CPU: 6 PID: 55 at fs/kernfs/dir.c:1706 kernfs_remove_by_name_ns+0xe9/0xf0 Workqueue: events ucsi_handle_connector_change [typec_ucsi] Call Trace: sysfs_remove_link+0x19/0x50 typec_unregister_partner+0x6e/0x120 [typec] ucsi_unregister_partner+0x107/0x150 [typec_ucsi] ucsi_handle_connector_change+0x3ec/0x490 [typec_ucsi] process_one_work+0x18e/0x3e0 worker_thread+0x2e3/0x420 kthread+0x10a/0x230 ret_from_fork+0x121/0x140 ret_from_fork_asm+0x1a/0x30

With worse timing the same stale pointer is dereferenced after the backing memory is freed, turning the warning into a use-after-free.

Fix the asymmetry: call typec_deattach() before clearing port_dev->connector, matching what connector_bind() does on the bind side. typec_partner_deattach() is already protected by port->partner_link_lock, so it serialises safely with the concurrent typec_unregister_partner() path.