CVE-2022-49009

What it actually does

Missing NULL check after devm_kcalloc in asus-ec-sensors hwmon driver allows NULL pointer dereference on allocation failure.

Why it matters to the business

Potential kernel crashes or system instability on affected Linux systems using ASUS embedded controller sensors, especially under memory pressure; low exploitation likelihood limits widespread operational disruption.

How an attack unfolds

An attacker with local access triggers the sensor initialization code path during low-memory conditions, causing the unchecked devm_kcalloc return value to be dereferenced and resulting in a kernel panic or denial of service.

How to fix it

Update the Linux kernel to a version containing commit a41ec58ac352fd176d5808af847663dc890f6053 or later; apply the equivalent fix from stable trees where available.

How to confirm the fix worked

Confirm kernel source contains the added NULL check after devm_kcalloc in drivers/hwmon/asus-ec-sensors.c; test probe under memory-constrained conditions to ensure no dereference occurs.

Typical attack path

1. Obtain local access to a system running the vulnerable Linux kernel with asus-ec-sensors enabled.
2. Induce memory pressure to force devm_kcalloc failure in hwmon probe.
3. Trigger hardware monitoring sensor registration to reach the unchecked pointer dereference.
4. Observe resulting kernel oops or system crash.

How to detect it

Review kernel logs for NULL pointer dereference oops in asus-ec-sensors or hwmon during device probe; correlate with low-memory events.

What your security team should do

• Prioritize kernel updates on systems exposing ASUS EC sensors via hwmon.
• Monitor for upstream stable releases incorporating the fix.
• Restrict untrusted local access on affected hardware until patched.