CVE-2026-43421

/// Technical description

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

usb: gadget: f_ncm: Fix net_device lifecycle with device_move

The network device outlived its parent gadget device during

disconnection, resulting in dangling sysfs links and null pointer

dereference problems.

A prior attempt to solve this by removing SET_NETDEV_DEV entirely [1]

was reverted due to power management ordering concerns and a NO-CARRIER

regression.

A subsequent attempt to defer net_device allocation to bind [2] broke

1:1 mapping between function instance and network device, making it

impossible for configfs to report the resolved interface name. This

results in a regression where the DHCP server fails on pmOS.

Use device_move to reparent the net_device between the gadget device and

/sys/devices/virtual/ across bind/unbind cycles. This preserves the

network interface across USB reconnection, allowing the DHCP server to

retain their binding.

Introduce gether_attach_gadget()/gether_detach_gadget() helpe

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References