CVE-2022-49835 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
ALSA: hda: fix potential memleak in 'add_widget_node'
As 'kobject_add' may allocated memory for 'kobject->name' when return error. And in this function, if call 'kobject_add' failed didn't free kobject. So call 'kobject_put' to recycling resources.
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Analysis
by VulDB Data Team • 11/10/2025
The vulnerability identified as CVE-2022-49835 represents a memory leak issue within the Linux kernel's Advanced Linux Sound Architecture implementation, specifically affecting the hda (High Definition Audio) driver component. This flaw resides in the audio subsystem's handling of widget node management during hardware initialization processes. The vulnerability manifests when the kernel attempts to add widget nodes to the kernel object hierarchy through the kobject_add function, which is a fundamental component of the Linux kernel's device model framework. The issue occurs during audio hardware enumeration where the system creates dynamic kernel objects to represent audio components such as widgets, amplifiers, and mixers within the high definition audio subsystem.
The technical root cause of this vulnerability stems from improper resource management within the add_widget_node function, which is part of the hda driver's widget management code. When kobject_add fails during the widget node creation process, the function does not properly release the allocated kernel object structure that was previously allocated. This failure occurs because the code path does not account for the scenario where kobject_add might allocate memory for the kobject->name field when returning an error condition, but fails to clean up the parent kobject structure. The kobject_add function, which is part of the kernel's object model subsystem, can allocate additional memory for the name field when encountering certain error conditions, creating a memory allocation that becomes orphaned when the function returns an error code. This behavior directly violates proper resource management practices and creates a memory leak that can accumulate over time.
The operational impact of this memory leak vulnerability extends beyond simple resource consumption issues, as it can lead to progressive memory exhaustion on systems with extensive audio hardware configurations or those running for extended periods. The vulnerability affects systems that utilize high definition audio hardware, particularly those with complex audio topologies involving multiple widgets, amplifiers, and audio codec components. Attackers who can trigger the specific code path leading to this memory leak could potentially cause system instability, performance degradation, or in extreme cases, system crashes or denial of service conditions. The vulnerability is particularly concerning in embedded systems or server environments where audio hardware is present and systems operate continuously for extended periods, as the accumulated memory leaks could eventually exhaust available system memory. This type of vulnerability aligns with CWE-401: Improper Release of Memory and represents a classic case of resource management failure in kernel space code.
Mitigation strategies for this vulnerability involve applying the official kernel patch that implements proper resource cleanup when kobject_add fails, ensuring that kobject_put is called to release all allocated resources regardless of the function's success or failure status. System administrators should prioritize updating to kernel versions that contain the fix, typically kernel versions 5.19 and later, as these releases include the necessary code modifications to properly handle the resource cleanup scenario. The fix implements proper error handling by ensuring that when kobject_add returns an error, the associated kobject structure is properly released through the kobject_put function, preventing the memory leak from occurring. Organizations should also implement monitoring solutions to detect memory consumption patterns that might indicate the presence of this vulnerability, particularly in systems where audio hardware is actively utilized. Additionally, the vulnerability demonstrates the importance of following the ATT&CK framework's T1499.004: Resource Hijacking category, as improper resource management in kernel drivers can lead to system resource exhaustion attacks. The fix also reinforces proper kernel development practices related to the principle of least privilege and resource management, ensuring that all allocated resources are properly accounted for and released during error conditions.