CVE-2026-46021
Analyzed Analyzed - Analysis Complete
Use-After-Free in Linux Kernel Thermal Subsystem

Publication date: 2026-05-27

Last updated on: 2026-06-16

Assigner: kernel.org

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.
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Meta Information
Published
2026-05-27
Last Modified
2026-06-16
Generated
2026-06-16
AI Q&A
2026-05-27
EPSS Evaluated
2026-06-15
NVD
CVE-2026-46021
EUVD
EUVD-2026-32402
Affected Vendors & Products
Showing 4 associated CPEs
Vendor Product Version / Range
linux linux_kernel From 6.7 (inc) to 6.12.86 (exc)
linux linux_kernel From 4.2 (inc) to 6.6.140 (exc)
linux linux_kernel From 6.13 (inc) to 6.18.27 (exc)
linux linux_kernel From 6.19 (inc) to 7.0.4 (exc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-401 The product does not sufficiently track and release allocated memory after it has been used, making the memory unavailable for reallocation and reuse.
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Executive Summary

This vulnerability exists in the Linux kernel's thermal management subsystem. Specifically, when the function thermal_zone_device_register_with_trips() fails after adding a thermal governor to a thermal zone, the governor is not properly removed, which can cause a memory leak.

Additionally, the function thermal_zone_device_unregister() calls thermal_set_governor() without acquiring the necessary thermal zone lock first. This can cause a race condition with a governor update via sysfs, potentially leading to a use-after-free error.

The issue is addressed by adding calls to thermal_set_governor() in two places to ensure the governor is properly removed and to prevent these race conditions and memory leaks.

Impact Analysis

This vulnerability can lead to memory leaks and use-after-free conditions within the Linux kernel's thermal management code.

Memory leaks can degrade system performance over time by consuming resources unnecessarily.

Use-after-free vulnerabilities can potentially be exploited to cause system crashes or execute arbitrary code, which may compromise system stability and security.

Mitigation Strategies

The vulnerability has been resolved in the Linux kernel by fixing thermal zone governor cleanup issues. To mitigate this vulnerability, you should update your Linux kernel to the latest version that includes the fix for this issue.

  • Apply the kernel update that addresses the thermal zone governor cleanup problems.
  • Ensure that your system is running a kernel version released after 2026-05-27, when the fix was published.
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