CVE-2023-52864

What it actually does

Use-after-free style memory corruption in wmi_char_open() caused by relying on a now-overwritten filp->private_data pointer instead of deriving the WMI device via container_of() on the miscdevice after a device deletion in wmi_free_devices().

Why it matters to the business

Kernel memory corruption on affected Linux systems can lead to crashes, denial of service, or local privilege escalation, impacting hardware management and stability on platforms that expose WMI char devices.

How an attack unfolds

An attacker with local access triggers concurrent WMI device removal (via wmi_free_devices) while a process opens the associated char device; the stale private_data pointer then dereferences attacker-controlled or freed memory, enabling corruption.

How to fix it

Update the Linux kernel to the commit cf098e937dd125c0317a0d6f261ac2a950a233d6 or later stable releases that contain the fix; rebuild and deploy the updated kernel image across all affected systems.

How to confirm the fix worked

Verify the running kernel contains commit cf098e937dd125c0317a0d6f261ac2a950a233d6, inspect the wmi.c source for the container_of() usage in wmi_char_open(), and confirm absence of the original private_data assumption.

Typical attack path

1. Obtain local unprivileged access on a vulnerable Linux kernel
2. Locate or create conditions that invoke wmi_free_devices() for a target WMI device
3. Race or synchronize an open() call on the WMI char device node
4. Trigger memory corruption via the stale private_data pointer
5. Escalate privileges or cause denial of service from the resulting kernel state

How to detect it

Review kernel logs for oops/panic traces mentioning wmi_char_open, wmi_free_devices, or container_of failures; correlate with processes opening WMI char devices around device hot-removal events.

• wmi_char_open
• wmi_free_devices
• container_of
• filp->private_data

What your security team should do

• Apply the kernel fix immediately on all systems exposing WMI char devices
• Monitor for kernel oops or panic reports referencing wmi_char_open or wmi_free_devices
• Restrict unprivileged access to WMI device nodes via permissions or LSM policies until patched
• Include the updated kernel in standard patch and reboot cycles