Linux Kernel Netfilter nf_tables Double Hook Unregistration Vulnerability

A vulnerability in the Linux kernel's netfilter component, specifically in the nf_tables subsystem, has been identified. This issue arises from a double unregistration of hooks in the network namespace path. The vulnerability occurs because the __nft_release_hooks() function is called during the pre_netns exit phase, which first unregisters the hooks. Subsequently, the NETDEV_UNREGISTER event is triggered, causing the hooks to be unregistered again. This flaw can lead to inconsistencies and potential misuse of the netfilter hook management.

Impact

Exploitation of this vulnerability can cause a warning message to be logged, indicating a double unregistration of netfilter hooks. This could potentially lead to a use-after-free condition, where memory that has been freed is still accessed, causing undefined behavior or allowing for exploitation.