Linux Kernel Netfilter nf_tables Netdev Hook Release Vulnerability

A use-after-free vulnerability has been identified in the Linux kernel's netfilter component, specifically within the nf_tables subsystem. This issue arises when a virtual Ethernet (veth) device is released, prompting the release of its peer net namespace device. If the peer net namespace is also scheduled for removal, the device memory may be freed before the appropriate cleanup hooks are executed. This sequence of events leads to a memory access violation, where freed memory is incorrectly accessed, causing a kernel panic.

Impact

Exploitation of this vulnerability causes a use-after-free error, where the kernel attempts to access memory that has already been freed. This can lead to memory corruption, potentially allowing for arbitrary code execution or other malicious activities.

Reproduction

To reproduce this vulnerability, create a pair of virtual Ethernet devices (veth pair) and attach them to different network namespaces. Then, initiate the removal of one net namespace while simultaneously releasing the veth device. This will trigger the vulnerability by queuing the peer net namespace for removal before the necessary cleanup hooks can be executed, leading to a use-after-free condition.

Remediation

Users can upgrade to the latest stable version of the Linux kernel, where this vulnerability has been addressed. Instructions for downloading the patched version are available on the official Linux kernel website.