Lock Inversion Vulnerability in Linux Kernel Affecting Networking Features

CVE-2026-80845

What is CVE-2026-80845?

A vulnerability has been identified in the Linux kernel related to lock inversion in NAT keepalive functionality. Specifically, the 'nat_keepalive_work()' process traverses the state table while holding the 'net->xfrm.xfrm_state_lock'. However, it also tries to acquire 'x->lock', leading to potential deadlocks. This situation arises due to the conflicting lock acquisition order with the state deletion path during a NAT keepalive operation, which could result in operational failures. To mitigate this issue, the fix entails splitting the keepalive traversal into two distinct phases: initially collecting candidate states while maintaining the 'xfrm_state_lock', and afterwards processing the states with controlled lock acquisition for 'x->lock'. This resolution enhances robustness in the networking functionality of the Linux kernel.

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