CVE-2025-40234 in Linux
Summary
by MITRE • 12/04/2025
In the Linux kernel, the following vulnerability has been resolved:
platform/x86: alienware-wmi-wmax: Fix NULL pointer dereference in sleep handlers
Devices without the AWCC interface don't initialize `awcc`. Add a check before dereferencing it in sleep handlers.
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Analysis
by VulDB Data Team • 02/23/2026
The vulnerability CVE-2025-40234 represents a critical NULL pointer dereference issue within the Linux kernel's platform x86 subsystem, specifically affecting the alienware-wmi-wmax driver. This flaw exists in the sleep handler implementations where the driver attempts to dereference a pointer to the awcc structure without proper validation of its initialization status. The alienware-wmi-wmax driver is designed to support Dell Alienware laptops and their associated WMI (Windows Management Interface) interfaces, particularly those with the AWCC (Alienware Command Center) interface that provides advanced hardware control capabilities. The vulnerability manifests when the driver encounters devices that lack the AWCC interface, which is common in various Alienware laptop models that may not have this specific hardware component or firmware support.
The technical implementation of this vulnerability stems from inadequate null pointer validation within the sleep handler functions of the alienware-wmi-wmax driver. When the kernel initializes the driver for a device, it attempts to set up the awcc structure to manage communication with the Alienware hardware interface. However, in cases where the device does not support or lacks the AWCC interface, this structure remains uninitialized and retains a NULL value. The sleep handler functions, which are invoked during system suspend and resume operations, directly dereference this uninitialized pointer without checking whether it contains valid memory address information. This pattern violates fundamental kernel security principles and creates a potential crash condition that can lead to system instability or complete system lockup during power management transitions.
The operational impact of this vulnerability extends beyond simple system crashes, as it affects the reliability of power management operations on affected Alienware systems. During normal system operation, when the kernel attempts to handle sleep states, the driver's sleep handlers execute and immediately trigger a NULL pointer dereference, resulting in kernel oops or system panics. This issue is particularly concerning because power management operations are frequent and critical system functions that occur during normal user interactions such as laptop lid closure, automatic sleep due to inactivity, or system shutdown procedures. The vulnerability affects all Linux kernel versions where the alienware-wmi-wmax driver is present and where the system is configured to use WMI-based power management features. Attackers could potentially exploit this vulnerability to cause denial of service conditions, though the direct exploitation for privilege escalation or remote code execution appears limited given the nature of the flaw.
This vulnerability maps directly to CWE-476, which defines NULL Pointer Dereference as a weakness where a null value is used as a pointer, and it aligns with ATT&CK technique T1490, specifically "Inhibit System Recovery" through system instability or crash conditions. The fix implemented addresses the core issue by adding proper null pointer checks before any dereference operations occur within the sleep handler functions. The solution involves modifying the driver code to verify that the awcc structure pointer is properly initialized before attempting to access its members or invoke functions through it. This remediation follows standard kernel development practices for defensive programming and adheres to the principle of least privilege by ensuring that all pointer accesses are validated before execution. The patch demonstrates proper error handling and graceful degradation when hardware components are not available, which is essential for maintaining system stability in heterogeneous hardware environments where different device configurations may exist within the same driver family. The resolution ensures that systems without the AWCC interface can still properly handle sleep operations without crashing, thereby maintaining the integrity of the power management subsystem and preventing potential denial of service scenarios that could affect user productivity and system availability.