CVE-2022-50866 in Linux
Summary
by MITRE • 12/30/2025
In the Linux kernel, the following vulnerability has been resolved:
ASoC: pxa: fix null-pointer dereference in filter()
kasprintf() would return NULL pointer when kmalloc() fail to allocate. Need to check the return pointer before calling strcmp().
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Analysis
by VulDB Data Team • 04/26/2026
The vulnerability CVE-2022-50866 represents a critical null-pointer dereference flaw within the Linux kernel's Advanced SoC (ASoC) subsystem, specifically affecting the pxa audio driver component. This issue resides in the filter() function where the kernel's audio subsystem fails to properly validate memory allocation outcomes before proceeding with string operations. The root cause stems from the kasprintf() function which, when encountering memory allocation failures during kmalloc() operations, returns a NULL pointer to the calling function. This fundamental flaw creates a dangerous condition where subsequent code execution attempts to invoke strcmp() on a NULL pointer, leading to immediate system termination through a kernel panic or potential privilege escalation.
The technical implementation of this vulnerability demonstrates poor error handling practices within kernel space programming, where the absence of proper null pointer validation creates a direct path for system instability. When the memory allocation fails, the system continues execution without proper error recovery mechanisms, directly violating fundamental kernel security principles. The vulnerability operates at the intersection of memory management and string processing functions, where the failure to check return values creates a classic null pointer dereference scenario that can be exploited by malicious actors to disrupt system operations. This flaw specifically impacts the PXA (PXA2xx) audio subsystem within the ASoC framework, which is commonly found in embedded systems and mobile devices that utilize these processors for audio processing capabilities.
The operational impact of this vulnerability extends beyond simple system crashes, potentially enabling denial of service attacks against embedded systems that rely on the affected audio drivers. Attackers could exploit this condition to repeatedly trigger memory allocation failures, causing repeated kernel panics and system instability. In environments where audio functionality is critical for system operation or where the affected devices are deployed in mission-critical applications, this vulnerability could lead to complete system unavailability. The vulnerability's exploitation requires minimal privileges since it operates within kernel space, making it particularly dangerous as it can be triggered by unprivileged users or processes that have access to audio subsystem interfaces.
Mitigation strategies for CVE-2022-50866 must focus on implementing robust error handling within the kernel's audio subsystem. The primary fix involves adding proper null pointer checks immediately after kasprintf() calls, ensuring that the returned pointer is validated before any subsequent string operations are performed. This approach aligns with CWE-476, which specifically addresses null pointer dereference vulnerabilities in software development. System administrators should prioritize applying kernel updates that include the patched version of the pxa audio driver, as this vulnerability affects multiple kernel versions and embedded device configurations. Additionally, implementing runtime monitoring for kernel memory allocation failures can help detect potential exploitation attempts, though such monitoring should be carefully implemented to avoid introducing additional system overhead. The fix demonstrates the importance of defensive programming practices in kernel development, where every memory allocation must be validated before use, as outlined in various kernel security best practices and ATT&CK framework considerations for kernel-level exploits.