# 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.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-90178, DEBIAN-CVE-2026-90178, GHSA-r39r-j9pr-wc8x, UBUNTU-CVE-2026-90178

## 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.

## Is CVE-2026-90178 being exploited?

There is no known exploitation of CVE-2026-90178 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90178 and fix it if it is affected.

What it is: 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.
Exploitation: There is no known exploitation of CVE-2026-90178 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-90178/ (Markdown: https://insights.sbomify.com/CVE-2026-90178/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90178
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90178
- OSV: https://osv.dev/vulnerability/CVE-2026-90178

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90178/
Summaries are generated and may contain mistakes; the official description above is the record.