# CVE-2026-98200: hwmon: (hp-wmi-sensors) Fix use-after-free in fungible_show()

> A race condition in the hp-wmi-sensors kernel driver allows local attackers to trigger a use-after-free, potentially leading to privilege escalation or code execution.

- **Severity:** Not scored
- **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:** Yes
- **Published:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106149, BELL-CVE-2026-98200, DEBIAN-CVE-2026-98200, GHSA-cww6-g46x-9cmq, UBUNTU-CVE-2026-98200

## What is CVE-2026-98200?

CVE-2026-98200 is an use after free vulnerability in Linux, published on 6 Oct 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: (hp-wmi-sensors) Fix use-after-free in fungible_show()

nsensor->current_state is dynamically replaced as the sensor's state
changes. update_numeric_sensor_from_wobj() does this by freeing the
old string and installing a new one:

	if (strcmp(trimmed, nsensor->current_state)) {
		new_string = hp_wmi_strdup(dev, trimmed);
		if (new_string) {
			devm_kfree(dev, nsensor->current_state);
			nsensor->current_state = new_string;
		}
	}

This function is only ever called from hp_wmi_update_info() while
state->lock is held, so the free-and-replace itself is properly
serialized against concurrent updates.

fungible_show(), however, reads the same pointer after the lock has
already been dropped:

	err = hp_wmi_update_info(state, info);
	if (err)
		return err;

	switch (prop) {
	...
	case HP_WMI_PROPERTY_CURRENT_STATE:
		seq_printf(seqf, "%s\n", nsensor->current_state);
		break;

hp_wmi_update_info() takes state->lock internally and releases it
before returning, so by the time fungible_show() dereferences
nsensor->current_state in seq_printf(), no lock is held. Two
processes reading a sensor's current_state debugfs entry at
overlapping times (or one reading it while another read of the same
sensor triggers a refresh) can race: one thread's seq_printf() can
be part-way through printing the string at the moment another
thread's call into update_numeric_sensor_from_wobj() frees it with
devm_kfree() and installs a new pointer, causing a use-after-free
read.

Take state->lock around the read in fungible_show() as well, so it
can never run concurrently with the free-and-replace in
update_numeric_sensor_from_wobj().

## Which versions are affected by CVE-2026-98200?


## How do I fix CVE-2026-98200?

Apply the vendor's patch.

## Is CVE-2026-98200 being exploited?

There is no known exploitation of CVE-2026-98200 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98200 and fix it if it is affected.

What it is: CVE-2026-98200 is an use after free vulnerability in Linux, published on 6 Oct 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-2026-98200 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-2026-98200/ (Markdown: https://insights.sbomify.com/CVE-2026-98200/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98200
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98200
- OSV: https://osv.dev/vulnerability/CVE-2026-98200

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98200/
Summaries are generated and may contain mistakes; the official description above is the record.