CVE-2021-47079

What it actually does

NULL pointer dereference occurs inside dytc_cql_command when the third parameter is passed as NULL and immediately dereferenced by the ideapad-laptop driver.

Why it matters to the business

Kernel panic on Lenovo IdeaPad systems can cause unexpected reboots, loss of unsaved work, and temporary denial of service for users or services running on the affected hardware.

How an attack unfolds

An attacker with local code execution triggers the DYTC CQL command path in the ideapad-laptop platform driver, supplying a NULL argument that the callee immediately dereferences, resulting in a kernel crash.

How to fix it

Apply the upstream kernel commit that ensures the third parameter to dytc_cql_command is never NULL; update to a patched kernel release containing the ideapad-laptop fix.

How to confirm the fix worked

Inspect the ideapad-laptop source for the corrected dytc_cql_command call site or confirm the patch is present in the running kernel via version string or git log.

Typical attack path

1. Obtain local execution on a vulnerable IdeaPad system
2. Interact with the ideapad-laptop module to reach dytc_cql_command
3. Supply NULL as the third parameter
4. Trigger immediate dereference leading to kernel oops/panic

How to detect it

Search kernel logs and crash dumps for NULL pointer dereference messages originating from the ideapad-laptop driver or dytc_cql_command function.

What your security team should do

• Prioritize kernel updates on all Lenovo IdeaPad devices
• Review kernel logs for oops involving ideapad-laptop after patching
• Disable the ideapad-laptop module if the hardware feature is unused