CVE-2026-64481 in Linux
Summary
by MITRE • 07/25/2026
In the Linux kernel, the following vulnerability has been resolved:
ALSA: hda/cs35l41: Fix firmware load work teardown
cs35l41_hda creates ALSA controls whose private data points at the cs35l41_hda object. The firmware load control can also queue fw_load_work.
Those controls are not removed on component unbind, and device remove only cancels fw_load_work through cs35l41_remove_dsp(). That helper is skipped when halo_initialized is false. With firmware_autostart disabled, a firmware load can be requested before the DSP has been initialized. If the component or device is removed before the queued work runs, the worker can run after teardown and dereference driver state that is no longer valid.
Track the created controls and remove them on unbind so no new control callback can reach the driver data or queue more work. Then cancel fw_load_work to drain any request that was already queued. Also cancel the work unconditionally during device remove before runtime PM teardown.
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Analysis
by VulDB Data Team • 07/26/2026
This vulnerability exists within the Linux kernel's Advanced Linux Sound Architecture implementation specifically affecting the cs35l41_hda driver component. The issue stems from improper cleanup of ALSA controls and firmware loading mechanisms during device removal or component unbind operations. The driver creates ALSA controls with private data pointers referencing the cs35l41_hda object structure, establishing a dependency chain that becomes problematic when the underlying hardware abstraction layer is torn down while asynchronous firmware loading operations remain pending.
The core technical flaw involves the improper handling of firmware load work queue management within the hda/cs35l41 subsystem. When firmware_autostart is disabled, firmware loading can be initiated before the DSP component has completed its initialization process. The cs35l41_remove_dsp() helper function, which normally cancels pending firmware load work through the fw_load_work mechanism, is conditionally skipped when halo_initialized is false. This conditional logic creates a window where queued firmware load operations may execute after the driver state has been partially or completely deallocated, resulting in use-after-free conditions and potential memory corruption.
The operational impact of this vulnerability manifests as a potential denial-of-service condition or arbitrary code execution vector within the kernel space. When device removal occurs before pending firmware load work completes, the worker thread executes against freed memory structures, potentially causing system crashes or enabling privilege escalation attacks. This represents a classic use-after-free vulnerability pattern that aligns with CWE-416 and follows ATT&CK technique T1068 for privilege escalation through kernel memory corruption.
The fix implemented addresses this by tracking all created ALSA controls during the component initialization phase and explicitly removing them during component unbind operations to prevent new control callbacks from accessing deallocated driver data. Additionally, the solution ensures unconditional cancellation of firmware load work during device removal before runtime power management teardown occurs, preventing any pending work from executing against invalid memory references. This comprehensive approach follows security best practices for resource management and cleanup in kernel drivers, ensuring proper synchronization between asynchronous operations and component lifecycle management while maintaining compliance with Linux kernel security standards and preventing potential exploitation through memory corruption attacks.
The vulnerability demonstrates the critical importance of proper resource cleanup and reference counting mechanisms in kernel space programming, particularly when dealing with asynchronous work queue management and hardware abstraction layers. The fix ensures that all driver state references are properly invalidated before memory deallocation occurs, preventing the execution of stale function pointers or access to freed memory structures that could otherwise be exploited by malicious actors to gain unauthorized system access or cause system instability through controlled memory corruption attacks.