CVE-2023-52781

What it actually does

The usb_get_bos_descriptor function fails to advance the read pointer when skipping USB_DT_DEVICE_CAPABILITY descriptors, resulting in the same descriptor being processed repeatedly instead of iterating to the next one.

Why it matters to the business

USB device enumeration may hang or consume excessive CPU resources on affected Linux systems, leading to system instability, delayed boot, or unresponsiveness when attaching certain USB peripherals.

How an attack unfolds

An attacker connects a USB device presenting a BOS descriptor containing capability descriptors that trigger the skip condition; the kernel enters a loop repeatedly reading the same data without pointer advancement, potentially exhausting resources during device initialization.

How to fix it

Upgrade the Linux kernel to a version containing commit 9ef94ec8e52eaf7b9abc5b5f8f5b911751112223 which introduces a goto to correctly update the pointer and read amount.

How to confirm the fix worked

Confirm the presence of the pointer advancement fix in usb/config.c by inspecting the source or verifying the commit hash in the running kernel build.

Typical attack path

1. Connect a USB device with a crafted BOS descriptor
2. Trigger usb_get_bos_descriptor during kernel enumeration
3. Exploit repeated descriptor read loop to impact system stability

How to detect it

Review kernel logs for repeated USB descriptor access patterns or high CPU during device enumeration; monitor dmesg and system logs around USB attach events for anomalies.

What your security team should do

• Apply the kernel update containing commit 9ef94ec8e52eaf7b9abc5b5f8f5b911751112223 across all affected systems
• Prioritize updates on systems with frequent USB device attachment
• Test USB enumeration behavior post-update with diverse peripherals