CVE-2026-46021 thermal: core: Fix thermal zone governor cleanup issues
A race condition in the Linux kernel thermal subsystem can lead to a use-after-free, potentially allowing code execution or 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-2026-46021?
CVE-2026-46021 is a medium-severity use after free vulnerability in Linux kernel, published on 27 May 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:
thermal: core: Fix thermal zone governor cleanup issues
If thermal_zone_device_register_with_trips() fails after adding a thermal governor to the thermal zone being registered, the governor is not removed from it as appropriate which may lead to a memory leak.
In turn, thermal_zone_device_unregister() calls thermal_set_governor() without acquiring the thermal zone lock beforehand which may race with a governor update via sysfs and may lead to a use-after-free in that case.
Address these issues by adding two thermal_set_governor() calls, one to thermal_release() to remove the governor from the given thermal zone, and one to the thermal zone registration error path to cover failures preceding the thermal zone device registration.
Weakness: CWE-401
Which versions are affected by CVE-2026-46021?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-46021?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-46021 being exploited?
There is no known exploitation of CVE-2026-46021 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as AZL-88664, BELL-CVE-2026-46021, DEBIAN-CVE-2026-46021, GHSA-7x76-cw6q-rm95, ROOT-OS-DEBIAN-11-CVE-2026-46021, ROOT-OS-DEBIAN-12-CVE-2026-46021 and 3 more.