CVE-2026-74547 hwmon: (adt7470) Fix busy-loop and I2C flooding in update thread
A local attacker with sysfs write access can cause a CPU busy-loop and I2C bus flooding in the adt7470 hardware monitoring driver by setting specific parameters to zero.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-74547?
CVE-2026-74547 is a denial of service vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (adt7470) Fix busy-loop and I2C flooding in update thread
When userspace configures 'auto_update_interval' to 0 via sysfs, the background kthread executes schedule_timeout_interruptible(0), which returns immediately.
If 'num_temp_sensors' is concurrently or previously set to 0, the msleep_interruptible() delay inside adt7470_read_temperatures() also becomes 0. This combination forces the background thread into a tight, unbounded busy-loop, hogging the CPU and flooding the I2C bus with a continuous stream of transactions.
Fix this vulnerability by raising the lower limit of the clamp_val in auto_update_interval_store() from 0 to 500 milliseconds. This guarantees a reasonable minimum sleep window between sensor updates, protecting the system from intentional or accidental I2C bus denial of service.
Which versions are affected by CVE-2026-74547?
How do I fix CVE-2026-74547?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-74547 being exploited?
There is no known exploitation of CVE-2026-74547 in the wild and no public exploit code.
Sources
Also known as AZL-96120, BELL-CVE-2026-74547, DEBIAN-CVE-2026-74547, GHSA-5cx6-pvh7-gm4r, UBUNTU-CVE-2026-74547.