Executive brief
In the Linux kernel, the following vulnerability has been resolved:
ieee802154: 6lowpan: fix NULL dereference in lowpan_newlink
TUNSETLINK allows a TUN device to change its link-layer type to ARPHRD_IEEE802154 without initializing ieee802154_ptr. lowpan_newlink() checks only the device type before dereferencing the pointer, so an RTM_NEWLINK request can trigger a NULL pointer dereference.
Reject devices without ieee802154_ptr along with devices of the wrong type.