CVE-2022-49009 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (asus-ec-sensors) Add checks for devm_kcalloc
As the devm_kcalloc may return NULL, the return value needs to be checked to avoid NULL poineter dereference.
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Analysis
by VulDB Data Team • 01/18/2026
The vulnerability identified as CVE-2022-49009 resides within the Linux kernel's hardware monitoring subsystem, specifically affecting the asus-ec-sensors driver component. This driver interface manages hardware sensors for ASUS motherboards and systems, providing essential temperature and voltage monitoring capabilities for system health assessment. The flaw manifests in how the driver handles memory allocation operations, creating a potential pathway for system instability and denial of service conditions when hardware sensor data is being processed.
The technical root cause involves the improper handling of memory allocation functions within the driver's implementation. The asus-ec-sensors driver utilizes devm_kcalloc, a kernel memory allocation function designed to allocate and zero-initialize memory blocks for device management. However, the driver fails to validate the return value from this allocation function, which can legitimately return NULL when memory allocation fails. This oversight creates a direct path for a NULL pointer dereference condition when the driver subsequently attempts to access the memory location that was never successfully allocated.
When devm_kcalloc returns NULL, the driver continues execution without proper error handling, leading to immediate system instability. The NULL pointer dereference occurs during normal sensor data processing operations, making this vulnerability particularly dangerous as it can be triggered through routine system monitoring activities. The impact extends beyond simple system crashes to potentially enabling privilege escalation or persistent denial of service conditions that could affect system availability and reliability.
This vulnerability aligns with CWE-476, which specifically addresses NULL pointer dereference conditions in software systems. The flaw represents a classic memory safety issue where proper error handling mechanisms are absent from critical resource allocation paths. From an operational security perspective, this vulnerability demonstrates the critical importance of proper resource management and defensive programming practices in kernel space code, where memory allocation failures can have catastrophic consequences for system stability.
The mitigation strategy requires implementing proper NULL pointer validation immediately following memory allocation calls within the asus-ec-sensors driver. This involves adding conditional checks to verify that devm_kcalloc returns valid memory addresses before proceeding with subsequent operations. System administrators should prioritize applying the relevant kernel security patches that address this specific memory management flaw, ensuring that all affected ASUS hardware monitoring systems receive the necessary updates to prevent potential exploitation. Additionally, organizations should implement comprehensive monitoring for anomalous system behavior that might indicate exploitation attempts, given the denial of service potential inherent in this vulnerability.