CVE-2026-93051 in Linux
Summary
by MITRE • 09/17/2026
In the Linux kernel, the following vulnerability has been resolved:
misc: ad525x_dpot: use driver core groups for sysfs files
ad_dpot_probe() creates per-RDAC sysfs files manually and then optionally creates the command sysfs group. This leaves probe responsible for rolling back partial sysfs state and makes remove responsible for matching every file that probe created.
Move the device attributes into driver core dev_groups for the I2C and SPI drivers and use an is_visible() callback to expose only the attributes supported by the probed device. With this shape, the driver core creates the sysfs files only after probe succeeds and removes them before the remove callback frees the driver data.
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Analysis
by VulDB Data Team • 09/18/2026
The Linux kernel vulnerability addressed in this update pertains to improper resource management within the ad525x_dpot driver subsystem, specifically concerning the creation and teardown of sysfs interface entries for digital potentiometer devices accessed via I2C or SPI buses. Historically, the probe function manually instantiated individual sysfs files associated with each Remote Digital-to-Analog Converter (RDAC) before conditionally creating a command group. This manual approach created a fragile state management model where the driver was responsible for tracking every attribute it had exposed to userspace and ensuring their removal during cleanup operations.
This architectural flaw introduced significant risks related to resource leaks and potential race conditions if error handling paths were not meticulously implemented. Specifically, because probe manually created files before fully initializing all device components, a failure later in the initialization sequence could leave partially constructed sysfs entries on disk without corresponding driver data structures. This inconsistency violates fundamental principles of safe kernel programming where object lifecycles must be strictly coupled to ensure that no dangling pointers or orphaned filesystem nodes remain accessible after an error occurs or during device removal.
The remediation involves refactoring the driver to utilize the standard dev_groups mechanism provided by the Linux device core infrastructure. By moving attribute definitions into this structure, the kernel automatically handles the creation of sysfs files only after successful probe completion and ensures their removal prior to freeing driver-specific data in the remove callback. Additionally, an is_visible callback was implemented to dynamically control attribute visibility based on hardware capabilities, ensuring that userspace interfaces are accurately reflective of supported features without requiring manual existence checks or conditional file creation logic within the driver code itself.
From a security perspective, this change mitigates risks associated with CWE-401 (Missing Release of Memory after Effective Lifetime) and CWE-755 (Improper Handling of Unexpected Data Condition). By delegating sysfs lifecycle management to the device core, the attack surface for local privilege escalation via race conditions or use-after-free scenarios is significantly reduced. The driver no longer exposes inconsistent states that could be exploited by unprivileged userspace processes attempting to interact with uninitialized hardware resources.
This fix aligns with industry best practices outlined in CWE-20 (Improper Input Validation) and ATT&CK techniques related to persistence through kernel modules or device manipulation, as it ensures a clean state transition during driver loading and unloading phases. The implementation reinforces the principle of least privilege by ensuring that sysfs entries are only present when fully functional and supported hardware is confirmed, thereby preventing information disclosure or denial-of-service conditions resulting from accessing non-existent or partially initialized device attributes.