CVE-2026-64488 in Linux
Summary
by MITRE • 07/25/2026
In the Linux kernel, the following vulnerability has been resolved:
ALSA: aoa: check snd_ctl_new1() return value
snd_ctl_new1() can return NULL when memory allocation fails. In layout.c, the function does not check the return value before dereferencing ctl->id.name or passing to aoa_snd_ctl_add(), which can lead to a NULL pointer dereference.
Add NULL checks after snd_ctl_new1() calls and return early if any fails.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 07/26/2026
The vulnerability resides within the Advanced Linux Sound Architecture implementation in the Linux kernel specifically affecting the audio over appliance (aoa) subsystem. This issue represents a classic null pointer dereference flaw that occurs during control device initialization. The problem manifests when the snd_ctl_new1() function fails to allocate memory for control elements, returning NULL instead of a valid control structure pointer. The layout.c file contains the problematic code path where this return value is not properly validated before subsequent operations are performed.
The technical execution of this vulnerability begins with memory allocation failure during control element creation through snd_ctl_new1(). When this function fails, it returns NULL to indicate the unsuccessful allocation attempt. However, the existing code does not validate this return value before proceeding with operations on the potentially null pointer. The code attempts to access ctl->id.name member and passes the null pointer to aoa_snd_ctl_add() function, creating a scenario where a null pointer dereference occurs during kernel execution.
This vulnerability directly maps to CWE-476 which defines NULL Pointer Dereference as a condition where a null value is used in a context that expects a valid object reference. The operational impact of this flaw can result in system instability and potential denial of service conditions within the audio subsystem. When triggered, the kernel will crash or panic due to the invalid memory access, potentially affecting audio functionality and system stability for users relying on audio over appliance hardware.
The attack surface for this vulnerability is primarily limited to systems utilizing the aoa subsystem with audio over appliance hardware configurations. The exploit requires a specific condition where memory allocation fails during control device creation, which typically occurs under memory pressure or resource exhaustion scenarios. However, the impact extends beyond simple denial of service as it represents a kernel-level memory safety issue that could potentially be leveraged in more sophisticated attacks targeting system stability.
Mitigation strategies for this vulnerability involve implementing proper error handling mechanisms after each call to snd_ctl_new1(). The recommended approach requires adding explicit NULL checks immediately following the function call and returning early from the containing function when allocation failures occur. This defensive programming technique aligns with best practices outlined in the Linux kernel coding guidelines and follows the principle of validating all return values from memory allocation functions. Additionally, system administrators should ensure adequate memory resources are available to minimize the likelihood of allocation failures that could trigger this condition.
The fix demonstrates proper kernel security practices by addressing the root cause through defensive programming rather than attempting to handle the error after it occurs. This approach prevents potential exploitation scenarios while maintaining the expected functionality of the audio subsystem. The solution maintains backward compatibility while strengthening the code's resilience against memory allocation failures, which represents a fundamental security principle in kernel development and aligns with the ATT&CK framework's emphasis on preventing privilege escalation through memory safety issues.
This vulnerability exemplifies the importance of comprehensive error handling in kernel space code where resource exhaustion can lead to critical system failures. The fix ensures proper resource management and prevents potential exploitation vectors that could arise from improper null pointer validation in kernel subsystems. The implementation follows established security patterns recommended for kernel development environments and helps maintain overall system integrity when dealing with audio hardware interfaces through the aoa subsystem.