CVE-2021-47344

What it actually does

The vulnerability causes a memory leak in the zr364xx USB video driver when usb_submit_urb() fails during read pipe initialization, leaving allocated URBs unreleased.

Why it matters to the business

Systems using affected Linux kernel versions with zr364xx hardware may experience gradual memory depletion over time, potentially leading to system instability or crashes during prolonged operation or repeated device interactions.

How an attack unfolds

An attacker with local access or control over USB devices can trigger repeated failures in usb_submit_urb calls within the zr364xx driver initialization, causing kernel memory to be allocated without being freed, exhausting available memory resources.

How to fix it

Update the Linux kernel to a version that includes the fix for the memory leak in zr364xx_start_readpipe function.

How to confirm the fix worked

Verify kernel source or changelog for the patch resolving non-freed URB in zr364xx driver; monitor memory usage with the driver loaded.

Typical attack path

1. Gain local access to the system
2. Insert or manipulate a zr364xx USB device
3. Trigger conditions leading to usb_submit_urb failure
4. Repeat to amplify memory leak

How to detect it

Examine kernel logs for zr364xx driver errors related to URB submission failures; use memory profiling tools to detect leaks associated with usb_alloc_urb calls in the driver.

What your security team should do

• Apply kernel updates promptly
• Disable zr364xx module if not needed
• Monitor for memory leaks in USB subsystems