CVE-2026-97414 in Linux
Summary
by MITRE • 09/24/2026
In the Linux kernel, the following vulnerability has been resolved:
ASoC: mediatek: mt8365-afe-pcm: fix possible NULL-pointer dereferences in mt8365_afe_suspend()
mt8365_afe_suspend() allocates the register backup buffer with devm_kcalloc(), but does not check for allocation failure before using the returned pointer. This may lead to a NULL pointer dereference when accessing afe->reg_back_up[i].
Add the missing NULL check and return -ENOMEM on allocation failure after disabling the main clock.
Also propagate the return value of mt8365_afe_suspend() in mt8365_afe_dev_runtime_suspend() so that the suspended state is not updated when suspend fails.
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Analysis
by VulDB Data Team • 09/24/2026
The vulnerability identified within the Linux kernel's ALSA System on Chip subsystem for MediaTek MT8365 platforms involves a critical NULL pointer dereference flaw located in the mt8365_afe_suspend function. This issue arises from an improper handling of memory allocation failures during system power management operations. Specifically, the driver attempts to allocate a buffer for backing up hardware registers using devm_kcalloc but fails to verify whether this allocation was successful before proceeding to use the returned pointer. In low-memory conditions or under heavy system load, dynamic memory allocations can fail and return NULL instead of a valid memory address. Without an explicit check for this condition, subsequent code attempts to access elements within the afe->reg_back_up array using this invalid pointer, triggering a kernel panic due to an illegal memory access operation.
From a technical perspective, this flaw represents a classic resource management error where the assumption that allocation will always succeed is not validated against reality. The absence of a NULL check violates fundamental defensive programming principles required for robust driver development. When the system enters a suspend state, the audio frontend must preserve its configuration by saving register values to memory so they can be restored upon resume. If this backup buffer cannot be allocated due to resource constraints and the code proceeds anyway, it attempts to write data into non-existent memory space controlled by the kernel's strict protection mechanisms. This results in an immediate crash of the operating system core, effectively causing a denial of service for the entire device rather than just the audio subsystem.
The operational impact of this vulnerability is significant as it affects system stability during power state transitions. Users may experience unexpected reboots or freezes when attempting to suspend their devices, particularly if memory pressure is high at that moment. This undermines the reliability of the platform and can lead to data loss if unsaved work exists on the device prior to the crash. Furthermore, because this occurs in a core subsystem like ASoC, it may prevent the system from entering low-power states correctly, leading to increased battery drain or thermal issues due to components remaining active when they should be suspended.
To mitigate this risk, developers must implement rigorous error handling for all dynamic memory allocations within kernel drivers. The primary remediation involves adding a conditional check immediately after calling devm_kcalloc to verify that the returned pointer is not NULL. If the allocation fails, the function should gracefully handle the error by returning an appropriate error code such as -ENOMEM and ensuring that any previously acquired resources, like clocks, are properly released before exiting. Additionally, it is crucial to propagate these return values up the call stack through mt8365_afe_dev_runtime_suspend to ensure that higher-level power management frameworks do not incorrectly mark the device as suspended when the operation actually failed. This ensures state consistency and prevents further logical errors during subsequent resume operations.
This vulnerability aligns with Common Weakness Enumeration CWE-476, which describes a NULL Pointer Dereference where code attempts to use an object pointer that is null instead of pointing to valid memory. It also relates to CWE-252, Check for Unusual or Exceptional Conditions, as the driver failed to check for the exceptional condition of allocation failure. In terms of adversarial tactics, while this specific instance appears to be a non-malicious coding oversight rather than an exploitable security flaw targeted by attackers, it falls under MITRE ATT&CK technique T1499, Endpoint Denial of Service, as successful exploitation would result in the unavailability of the endpoint. Ensuring robust error handling and validation of external inputs or resource availability is essential for maintaining system integrity and preventing such stability issues across embedded Linux environments.