CVE-2021-46944

What it actually does

A reference to allocated memory is lost in the imu_fmt function of the intel-ipu3 media driver when an error check occurs before assignment, resulting in a kernel memory leak.

Why it matters to the business

Local users on affected Linux systems can trigger repeated leaks that exhaust memory, leading to degraded performance, instability, or denial of service; high kernel prevalence increases exposure across servers, desktops, and embedded devices despite low exploitation likelihood.

How an attack unfolds

An attacker with local access invokes the intel-ipu3 driver code path, forces the faulty check ordering in imu_fmt to discard the allocation reference, and repeats the operation to accumulate unreferenced memory until system resources are depleted.

How to fix it

Apply the upstream kernel patch that reorders the check in imu_fmt to retain the allocation reference; rebuild and deploy updated kernels on all affected systems.

How to confirm the fix worked

Inspect the imu_fmt function in the intel-ipu3 staging driver source to confirm the allocation occurs before the error check; run memory-leak detection tools or kernel fuzzers targeting the media subsystem.

Typical attack path

1. Gain local user access on a Linux system using the intel-ipu3 driver
2. Trigger the imu_fmt code path through media subsystem interaction
3. Force the error condition that loses the allocation reference
4. Repeat to accumulate leaked memory and induce resource exhaustion

How to detect it

Review kernel logs and dmesg output for repeated allocation warnings or failures originating from the intel-ipu3 driver; correlate with processes accessing the media subsystem.

What your security team should do

• Apply kernel updates containing the imu_fmt fix as soon as available
• Restrict untrusted local access on systems exposing the intel-ipu3 driver
• Monitor memory usage patterns in media-related processes for anomalous growth