CVE-2010-5329

What it actually does

The video_usercopy function in drivers/media/video/v4l2-ioctl.c relies on an attacker-supplied count value from a v4l2_ext_controls structure to compute a kmalloc size, allowing excessive memory allocation without validation.

Why it matters to the business

Local denial-of-service conditions on Linux systems can disrupt video-related workloads and cause system instability or crashes, increasing operational overhead for availability-sensitive environments.

How an attack unfolds

A local attacker opens a video device node, crafts a v4l2_ext_controls structure with an arbitrarily large count, and invokes the corresponding ioctl to trigger an oversized kernel memory allocation that exhausts resources.

How to fix it

Upgrade the Linux kernel to version 2.6.39 or later; apply vendor-supplied backports where available and rebuild any custom modules that interact with v4l2 ioctls.

How to confirm the fix worked

Verify the running kernel version is 2.6.39 or newer; confirm absence of the vulnerable video_usercopy logic via source inspection or by testing that large count values are rejected or capped.

Typical attack path

1. Obtain local user access on a Linux system exposing video4linux devices
2. Open a /dev/video* device node
3. Prepare and submit a v4l2_ext_controls ioctl with a large count value
4. Trigger repeated allocations to induce memory pressure or OOM conditions

How to detect it

Review kernel logs for unusually large kmalloc failures or OOM killer invocations correlated with video ioctl activity; inspect audit logs for unexpected access to video device nodes.

What your security team should do

• Prioritize kernel upgrades on systems with video4linux exposure
• Restrict local access to video devices via device permissions and SELinux/AppArmor policies
• Monitor kernel update channels for any remaining distribution-specific fixes