# CVE-2026-74552: hwmon: (lm90) Only report alarms if driver is ready

> A local attacker can trigger a kernel crash by reading sysfs attributes before the lm90 driver is fully initialized, causing a null pointer dereference.

- **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:** 15 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** AZL-96252, BELL-CVE-2026-74552, DEBIAN-CVE-2026-74552, GHSA-ccxm-23rv-p7vf, UBUNTU-CVE-2026-74552

## What is CVE-2026-74552?

CVE-2026-74552 is a vulnerability in Linux, published on 15 Aug 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: (lm90) Only report alarms if driver is ready

Userspace can read sysfs attributes before driver registration is complete,
immediately after devm_hwmon_device_register_with_info() has been called.
At that time, data->hwmon_dev is not yet initialized. This can trigger
a NULL pointer access since lm90_update_device() and with it
lm90_update_alarms_locked() will be called. This call schedules
report_work and lm90_report_alarms(), which passes the still-NULL
data->hwmon_dev to hwmon_notify_event() and triggers a NULL pointer
dereference.

Fix the problem by only scheduling the report and alert workers
data->hwmon_dev is set.

## Which versions are affected by CVE-2026-74552?


## How do I fix CVE-2026-74552?

Apply the vendor's patch.

## Is CVE-2026-74552 being exploited?

There is no known exploitation of CVE-2026-74552 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74552 and fix it if it is affected.

What it is: CVE-2026-74552 is a vulnerability in Linux, published on 15 Aug 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-2026-74552 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-2026-74552/ (Markdown: https://insights.sbomify.com/CVE-2026-74552/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74552
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74552
- OSV: https://osv.dev/vulnerability/CVE-2026-74552

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74552/
Summaries are generated and may contain mistakes; the official description above is the record.