CVE-2022-49836 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
siox: fix possible memory leak in siox_device_add()
If device_register() returns error in siox_device_add(), the name allocated by dev_set_name() need be freed. As comment of device_register() says, it should use put_device() to give up the reference in the error path. So fix this by calling put_device(), then the name can be freed in kobject_cleanup(), and sdevice is freed in siox_device_release(), set it to null in error path.
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Analysis
by VulDB Data Team • 11/10/2025
The vulnerability identified as CVE-2022-49836 represents a memory leak in the Linux kernel's siox subsystem, specifically within the siox_device_add() function. This issue occurs during device registration processes where proper resource cleanup mechanisms are not adequately implemented. The siox subsystem is responsible for managing serial I/O eXtension devices, which are critical components in embedded systems and specialized hardware configurations. The flaw manifests when the device_register() function fails during device addition operations, leaving allocated memory resources in an inconsistent state.
The technical root cause of this vulnerability stems from improper error handling within the device registration flow. When device_register() returns an error condition, the function fails to properly release the device reference that was allocated by dev_set_name() during the initialization phase. According to kernel development best practices and the documented behavior of device_register(), the correct approach requires using put_device() to relinquish the device reference in error paths. This function call ensures that the kernel's reference counting mechanism properly manages the device lifecycle and allows for appropriate cleanup operations. The failure to implement this pattern results in a memory leak where device names and associated structures remain allocated in kernel memory.
The operational impact of this vulnerability extends beyond simple memory consumption issues, potentially leading to system instability and resource exhaustion over time. In embedded systems or environments with limited memory resources, such memory leaks can accumulate and eventually cause system crashes or degraded performance. The siox subsystem is commonly used in industrial control systems, automotive applications, and specialized hardware platforms where reliable device management is paramount. The vulnerability affects systems running Linux kernels where the siox subsystem is active, particularly those managing serial I/O devices through the siox framework. Attackers could potentially exploit this memory leak to cause denial of service conditions by repeatedly triggering device registration failures, leading to progressive memory consumption.
Mitigation strategies for this vulnerability focus on applying the appropriate kernel patch that implements the correct error handling pattern. The fix involves calling put_device() when device_register() returns an error, ensuring proper reference counting and resource cleanup. This approach aligns with the established kernel development practices and security guidelines for memory management. System administrators should prioritize applying the relevant kernel updates from their distribution vendors or directly from the Linux kernel source repository. The vulnerability classification aligns with CWE-401, which addresses improper handling of memory allocation failures, and relates to ATT&CK technique T1499.2, which covers resource exhaustion attacks. Organizations should implement regular kernel update policies and maintain current security patches to prevent exploitation of such memory management vulnerabilities. The fix demonstrates proper adherence to kernel subsystem design principles where error paths must properly clean up all allocated resources, ensuring that kobject_cleanup() can properly free the allocated device name and siox_device_release() handles the sdevice cleanup appropriately.