CVE-2022-1975

What it actually does

A sleep-in-atomic-context bug in net/nfc/netlink.c permits a local process to trigger a kernel panic by emulating an NFC device through the netlink interface.

Why it matters to the business

Local users can force kernel crashes on affected Linux systems, producing unplanned downtime and potential loss of availability for services running on those hosts.

How an attack unfolds

An attacker with local access opens the NFC netlink socket, registers a virtual device, and issues crafted operations that cause the kernel to sleep while holding an atomic lock, resulting in a panic.

How to fix it

Upgrade the Linux kernel to a version containing commit 4071bf121d59944d5cd2238de0642f3d7995a997 or later; rebuild and reboot with the patched kernel.

How to confirm the fix worked

Confirm the running kernel contains the referenced commit or a backport; attempt to reproduce the crash with a local NFC netlink emulator after patching to verify the defect is closed.

Typical attack path

1. Obtain a local shell or user context on the target system
2. Open the NFC netlink socket and register a simulated device
3. Issue netlink commands that exercise the vulnerable sleep path
4. Trigger the atomic-context violation to induce kernel panic

How to detect it

Review kernel logs (dmesg, /var/log/kern.log) for NFC netlink-related panics or warnings around the time of suspected incidents; correlate with process execution that interacts with netlink sockets.

What your security team should do

• Prioritize kernel upgrades on all internet-facing or multi-tenant Linux systems
• Limit unprivileged local accounts where feasible until patches are applied
• Include NFC netlink paths in kernel panic monitoring and alerting