CVE-2025-71111 hwmon: (w83791d) Convert macros to functions to avoid TOCTOU
A race condition in the w83791d hardware monitoring driver can cause divide-by-zero errors, leading to a denial of service.
- 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-2025-71111?
CVE-2025-71111 is a medium-severity vulnerability in Linux kernel, published on 14 Jan 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: (w83791d) Convert macros to functions to avoid TOCTOU
The macro FAN_FROM_REG evaluates its arguments multiple times. When used in lockless contexts involving shared driver data, this leads to Time-of-Check to Time-of-Use (TOCTOU) race conditions, potentially causing divide-by-zero errors.
Convert the macro to a static function. This guarantees that arguments are evaluated only once (pass-by-value), preventing the race conditions.
Additionally, in store_fan_div, move the calculation of the minimum limit inside the update lock. This ensures that the read-modify-write sequence operates on consistent data.
Adhere to the principle of minimal changes by only converting macros that evaluate arguments multiple times and are used in lockless contexts.
Which versions are affected by CVE-2025-71111?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-71111?
Apply the vendor's patch.
Is CVE-2025-71111 being exploited?
There is no known exploitation of CVE-2025-71111 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-71111, DEBIAN-CVE-2025-71111, GHSA-w25h-64gv-grq6, ROOT-OS-UBUNTU-2204-CVE-2025-71111, ROOT-OS-UBUNTU-2404-CVE-2025-71111, UBUNTU-CVE-2025-71111.