CVE-2026-90178 hwmon: (coretemp) Fix core_data leak on CPUs without PTS
A memory leak in the Linux kernel coretemp driver on CPUs without PTS support can lead to resource exhaustion and denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-90178?
CVE-2026-90178 is a memory corruption vulnerability in Linux, published on 17 Sep 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: (coretemp) Fix core_data leak on CPUs without PTS
pdata->core_data is allocated in init_temp_data() when the first core temp_data of a package is created, but it is only released from destroy_temp_data(), and only in the branch that handles the package temp_data.
Package temp_data is created solely when the CPU supports X86_FEATURE_PTS. On a CPU without it, coretemp_cpu_online() never calls coretemp_add_core() with pkg_flag set, so pdata->pkg_data stays NULL. coretemp_cpu_offline() then skips the removal of the package interface, destroy_temp_data() is never called for package data, and the array is still allocated when coretemp_device_remove() frees the platform data that pointed at it.
Release the array in coretemp_device_remove(). destroy_temp_data() sets pdata->core_data to NULL when it frees it, so the added kfree() is a no-op on CPUs that do have PTS.
Tested on an Intel Core i5-1135G7. The driver was instrumented to log every allocation and release of pdata->core_data, and the PTS check in coretemp_cpu_online() was patched out to emulate a CPU without package thermal support. Without this change the array was allocated and never released, and coretemp_device_remove() still saw a non-NULL pointer. With it the array is released and the pointer accounting balances. On an unmodified build the release still happens via the package temp_data and the added kfree() sees NULL, with no slab warnings over repeated module load and unload cycles.
Which versions are affected by CVE-2026-90178?
How do I fix CVE-2026-90178?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-90178 being exploited?
There is no known exploitation of CVE-2026-90178 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-90178, DEBIAN-CVE-2026-90178, GHSA-r39r-j9pr-wc8x, UBUNTU-CVE-2026-90178.