CVE-2025-37969

What it actually does

The st_lsm6dsx_read_tagged_fifo function enters an infinite loop when pattern_len equals zero while the device FIFO remains non-empty, resulting in a kernel-level denial of service.

Why it matters to the business

Systems using affected Linux kernel versions with the st_lsm6dsx IMU driver may experience unresponsiveness or hangs, disrupting operations on devices relying on this sensor hardware; widespread kernel prevalence increases exposure across embedded and server deployments.

How an attack unfolds

An attacker with local access or the ability to influence the sensor FIFO state manipulates conditions so that pattern_len becomes zero while data remains buffered, triggering the infinite loop in the read function and locking up the affected kernel thread.

How to fix it

Apply the kernel patch from commit 4db7d923a8c298788181b796f71adf6ca499f966 or upgrade to a stable Linux kernel release containing this fix; rebuild and deploy the updated kernel across all affected systems.

How to confirm the fix worked

Confirm the running kernel includes commit 4db7d923a8c298788181b796f71adf6ca499f966 via git log or uname output; test by exercising the FIFO read path with pattern_len=0 to verify the loop no longer occurs.

Typical attack path

1. Identify a target system running an unpatched Linux kernel with the st_lsm6dsx driver enabled and the IMU device present.
2. Trigger or wait for a state where the FIFO contains data but pattern_len is set to zero.
3. Invoke the st_lsm6dsx_read_tagged_fifo path, causing the loop condition to activate.
4. Observe sustained kernel thread hang leading to denial of service.

How to detect it

Review kernel logs and process traces for repeated calls or stalls originating from st_lsm6dsx_read_tagged_fifo; correlate with IMU device activity and watchdog timeouts indicating thread hangs.

What your security team should do

• Prioritize kernel upgrades containing commit 4db7d923a8c298788181b796f71adf6ca499f966 on all systems using the st_lsm6dsx driver.
• Monitor for kernel updates from distribution vendors and apply within standard patch windows.
• Review sensor driver configurations to minimize unnecessary FIFO usage where possible.