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/f9a43007d3f7ba76d5e7f9421094f00f2ef202f8
https://git.kernel.org/stable/c/c73955a09408e7374d9abfd0e78ce3de9cda0635
https://git.kernel.org/stable/c/b09e6ccf0d12f9356e8e3508d3e3dce126298538
https://git.kernel.org/stable/c/a3940dcf552f2393d1e8f263b386593f98abe829
https://git.kernel.org/stable/c/9c413a8c8bb49cc16796371805ecb260e885bb2b
https://git.kernel.org/stable/c/86c0154f4c3a56c5db8b9dd09e3ce885382c2c19
https://git.kernel.org/stable/c/3fac8ce48fa9fd61ee9056d3ed48b2edefca8b82