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

netfilter: nf_tables: double hook unregistration in netns path

__nft_release_hooks() is called from pre_netns exit path which
unregisters the hooks, then the NETDEV_UNREGISTER event is triggered
which unregisters the hooks again.

[  565.221461] WARNING: CPU: 18 PID: 193 at net/netfilter/core.c:495 __nf_unregister_net_hook+0x247/0x270
[...]
[  565.246890] CPU: 18 PID: 193 Comm: kworker/u64:1 Tainted: G            E     5.18.0-rc7+ #27
[  565.253682] Workqueue: netns cleanup_net
[  565.257059] RIP: 0010:__nf_unregister_net_hook+0x247/0x270
[...]
[  565.297120] Call Trace:
[  565.300900]  <TASK>
[  565.304683]  nf_tables_flowtable_event+0x16a/0x220 [nf_tables]
[  565.308518]  raw_notifier_call_chain+0x63/0x80
[  565.312386]  unregister_netdevice_many+0x54f/0xb50

Unregister and destroy netdev hook from netns pre_exit via kfree_rcu
so the NETDEV_UNREGISTER path see unregistered hooks.

https://git.kernel.org/stable/c/3fac8ce48fa9fd61ee9056d3ed48b2edefca8b82

https://git.kernel.org/stable/c/86c0154f4c3a56c5db8b9dd09e3ce885382c2c19

https://git.kernel.org/stable/c/9c413a8c8bb49cc16796371805ecb260e885bb2b

https://git.kernel.org/stable/c/a3940dcf552f2393d1e8f263b386593f98abe829

https://git.kernel.org/stable/c/b09e6ccf0d12f9356e8e3508d3e3dce126298538

https://git.kernel.org/stable/c/c73955a09408e7374d9abfd0e78ce3de9cda0635

https://git.kernel.org/stable/c/f9a43007d3f7ba76d5e7f9421094f00f2ef202f8