CVE-2026-98674 in Linux
Summary
by MITRE • 10/18/2026
In the Linux kernel, the following vulnerability has been resolved:
iio: adc: adi-axi-adc: Initialize state mutex
The AXI ADC register access paths serialize transactions with st->lock, but probe does not initialize it. Initialize the mutex before registering the backend.
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Analysis
by VulDB Data Team • 10/19/2026
This advisory addresses a critical initialization flaw within the Linux kernel's Industrial I/O subsystem, specifically affecting the Analog Devices AXI ADC driver. The vulnerability stems from an improper handling of synchronization primitives during the device probing phase. In complex hardware drivers that manage concurrent access to shared resources, mutexes are essential for preventing race conditions and ensuring data integrity. However, in this specific implementation, while the code logic correctly utilizes a spinlock or mutex identified as st->lock to serialize transactions when accessing AXI ADC registers, the initialization routine fails to properly initialize this synchronization object before it is registered with the backend framework. This oversight creates a scenario where the kernel attempts to lock an uninitialized mutex structure, leading to undefined behavior that can manifest as system crashes, data corruption, or security vulnerabilities due to unsynchronized access patterns.
The technical root cause lies in the sequence of operations during driver initialization. When the kernel probes for hardware devices, it executes specific setup routines before making the device available to user-space applications and other kernel subsystems. The AXI ADC driver relies on st->lock to protect critical sections where register reads and writes occur. Because this mutex is not initialized via standard kernel APIs such as mutex_init prior to its first use in registration or subsequent operations, any thread attempting to acquire this lock will interact with garbage data or an invalid memory state. This can result in immediate kernel panics if the uninitialized structure contains pointers that lead to illegal memory accesses, or more insidiously, it may allow multiple threads to bypass synchronization checks entirely if the mutex internals are interpreted as unlocked by chance, thereby exposing a race condition vulnerability.
From an operational impact perspective, this flaw compromises system stability and potentially security posture. A local attacker with sufficient privileges to trigger device probing operations or interact with the Industrial I/O subsystem could induce a denial of service by causing kernel oopses or panics through repeated access attempts that hit the uninitialized lock path. Furthermore, if the race condition allows unsynchronized concurrent modifications to hardware registers or internal driver state structures, it may lead to data integrity issues where sensor readings are corrupted or device configurations are altered unexpectedly. In environments requiring high availability and strict reliability standards, such as industrial automation or aerospace systems utilizing these ADCs, this vulnerability poses a significant risk of operational disruption.
This issue aligns with CWE-665, which describes improper initialization of shared resources, specifically highlighting the failure to initialize synchronization primitives before use. It also relates to CWE-362 regarding concurrent execution using shared resources with insufficient synchronization. From an offensive security perspective, this type of flaw can be leveraged in privilege escalation attacks if it leads to memory corruption that allows for arbitrary code execution or kernel data disclosure. The ATT&CK framework categorizes such exploitation under techniques involving resource manipulation and potentially defense evasion through system instability, although the primary classification remains a reliability defect with secondary security implications due to the potential for exploitable race conditions.
To mitigate this vulnerability, it is imperative to ensure that all synchronization primitives are explicitly initialized before they are registered or used within any concurrent context. For developers maintaining the Linux kernel and its drivers, the fix involves inserting the appropriate initialization call, such as mutex_init(&st->lock), early in the probe function, prior to registering the backend device with the IIO subsystem. This ensures that when subsequent operations attempt to acquire the lock for serializing AXI ADC register access, the mutex is in a valid, locked-unlocked state ready for proper contention management. System administrators should apply kernel updates provided by their distribution vendors as soon as patches addressing this specific driver flaw are released, ensuring that the initialization sequence correctly precedes any hardware interaction or backend registration steps.