CVE-2024-46759

What it actually does

Improper input validation in the adc128d818 hwmon driver allows a large negative value supplied via kstrtol() to DIV_ROUND_CLOSEST() to produce an integer underflow before clamping occurs, resulting in incorrect or out-of-range limit values being written to the device.

Why it matters to the business

Local users on affected Linux systems can trigger unexpected hardware monitoring behavior that may lead to system instability, incorrect sensor data, or crashes, requiring urgent kernel updates across server and endpoint fleets to restore reliable operation.

How an attack unfolds

An attacker with local access writes a crafted large negative number to a limit sysfs attribute; the un-clamped value reaches DIV_ROUND_CLOSEST() and underflows, corrupting internal driver state and potentially allowing further memory corruption or denial of service.

How to fix it

Update the Linux kernel to the fixed commit 05419d0056dcf7088687e561bb583cc06deba777 or later stable release containing the reordered clamp_val() and DIV_ROUND_CLOSEST() operations; rebuild and reboot with the patched kernel image.

How to confirm the fix worked

Confirm the running kernel contains commit 05419d0056dcf7088687e561bb583cc06deba777, then attempt to write a large negative value to a limit attribute and verify that clamping occurs without underflow or kernel warnings.

Typical attack path

1. Obtain local shell or process execution on target system
2. Locate adc128d818 limit attribute files under /sys/class/hwmon
3. Write large negative value such as -9223372036854775808 to a limit attribute
4. Trigger underflow and observe resulting driver or system instability

How to detect it

Review kernel logs and audit trails for writes to adc128d818 limit attributes containing extreme negative values; correlate with any subsequent underflow warnings or hwmon driver oops messages.

What your security team should do

• Prioritize kernel updates on all systems exposing adc128d818 hardware monitoring
• Restrict unprivileged write access to hwmon sysfs attributes via mount options or SELinux policies until patched
• Monitor kernel logs for underflow-related warnings during the update window