CVE-2026-98680: Linux Kernel Information Disclosure Vulnerability

CVE-2026-98680 Overview

CVE-2026-98680 is a memory leak and state corruption vulnerability in the Linux kernel's Industrial I/O (IIO) subsystem, specifically within the kionix-kx022a accelerometer driver. The flaw resides in the kx022a_fifo_enable() function on the buffer enable path. When a regmap operation fails during buffer enablement, the driver fails to free previously allocated sample memory and does not revert hardware configuration changes. This leaves watermark interrupts and FIFO buffers enabled while driver state flags remain inconsistent with the actual hardware state.

Critical Impact
Repeated failure conditions can exhaust kernel memory and leave the accelerometer hardware in an inconsistent state, producing incorrect sensor data or unexpected interrupt behavior.

Affected Products

Linux kernel versions containing the kionix-kx022a IIO accelerometer driver
Systems using Kionix KX022A accelerometer hardware via the mainline kernel driver
Downstream distributions shipping affected kernel versions prior to the fix commits

Discovery Timeline

2026-10-18 - CVE-2026-98680 published to NVD
2026-10-19 - Last updated in NVD database

Technical Details for CVE-2026-98680

Vulnerability Analysis

The kionix-kx022a driver allocates memory for sample buffers when userspace enables the IIO buffer interface. The allocation occurs early in kx022a_fifo_enable(), followed by a series of regmap register writes that configure the hardware FIFO, sampling parameters, and watermark interrupts.

If any intermediate regmap call returns an error, the function exits without releasing the allocated sample memory. The driver also fails to undo the hardware configuration changes already applied, leaving watermark interrupts (WMI) and FIFO buffers enabled on the device. Internal driver state flags that track buffer enablement remain set despite the operation having failed.

The inconsistency between kernel state flags and actual hardware configuration can cause the driver to make incorrect assumptions on subsequent buffer operations. Repeated enable attempts under failing conditions compound the memory leak over time.

Root Cause

The root cause is missing error-path cleanup in kx022a_fifo_enable(). The function lacks the required goto-based unwinding to free allocated memory and revert partially applied hardware configuration when a regmap operation fails midway through the enable sequence. This is a classic resource leak pattern [CWE-401] combined with incomplete state rollback.

Attack Vector

Triggering the condition requires the ability to open the IIO device and enable the buffer interface, typically restricted to privileged users or processes with appropriate access to /sys/bus/iio/devices/. The underlying regmap failures depend on bus-level conditions such as I2C or SPI communication errors. Direct remote exploitation is not practical; the issue primarily affects reliability and long-running system stability on devices using this accelerometer.

The vulnerability is a kernel memory leak with state desynchronization. No code execution or privilege escalation is implied by the fix description. See the upstream patch commits for the exact code paths affected.

Detection Methods for CVE-2026-98680

Indicators of Compromise

Growing kernel slab allocations attributable to IIO sample buffers over time on systems using the kionix-kx022a driver
Repeated error entries in dmesg referencing kx022a or regmap write failures during buffer enablement
Accelerometer devices reporting stale or inconsistent data after a failed enable sequence

Detection Strategies

Compare installed kernel package versions against the fixed commits 2ef953f, 5c7ca8f, e3bc345, and e65e128 referenced in the upstream advisory
Monitor /proc/slabinfo and /proc/meminfo on affected hardware for abnormal kernel memory growth
Audit kernel ring buffer logs for kx022a_fifo_enable failure traces following buffer open operations

Monitoring Recommendations

Collect dmesg and kernel audit logs from embedded or IoT devices equipped with Kionix KX022A sensors
Track long-term kernel memory baselines on systems that repeatedly cycle IIO buffer enable and disable operations
Alert on repeated IIO subsystem errors emitted by sensor drivers to catch bus-level faults early

How to Mitigate CVE-2026-98680

Immediate Actions Required

Identify systems running kernels that include the vulnerable kionix-kx022a driver and use Kionix KX022A hardware
Apply the upstream Linux kernel patches referenced by commits 2ef953f, 5c7ca8f, e3bc345, and e65e128
Update to a distribution kernel package that incorporates the fix for CVE-2026-98680

Patch Information

The fix adds proper error-path handling to kx022a_fifo_enable(). On failure, the allocated sample memory is freed, hardware configuration is reverted, and driver state flags are reset. Patch references: Kernel Git Commit 2ef953f, Kernel Git Commit 5c7ca8f, Kernel Git Commit e3bc345, and Kernel Git Commit e65e128.

Workarounds

Avoid enabling the IIO buffer interface on affected kionix-kx022a devices on vulnerable kernels where possible
Restrict access to IIO sysfs entries so only trusted processes can trigger buffer enablement
Blacklist the kionix-kx022a module on systems that do not require accelerometer functionality until the patch is applied

bash

# Blacklist the vulnerable driver module until patched
echo "blacklist kionix-kx022a" | sudo tee /etc/modprobe.d/blacklist-kionix.conf
sudo update-initramfs -u