Bug 2482118 (CVE-2026-46021)

Summary: CVE-2026-46021 kernel: thermal: core: Fix thermal zone governor cleanup issues
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's thermal management subsystem. This vulnerability can lead to a memory leak if a thermal governor is not correctly cleaned up during device registration failures. More critically, a race condition during thermal zone unregistration, where a governor update might conflict with the unregistration process, can result in a use-after-free error. A local attacker could potentially exploit this use-after-free to cause system instability, leading to a denial of service, or in some scenarios, achieve unauthorized code execution.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2026-05-27 15:12:11 UTC 
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.
Comment 1 Keith Grant 2026-05-27 20:28:10 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052746-CVE-2026-46021-095e@gregkh/T