# CVE-2026-74546: hwmon: (adt7470) Fix divide-by-zero TOCTOU crash in fan speed read

> A race condition in the adt7470 hardware monitoring driver causes a divide-by-zero crash, leading to local 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:** 15 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** AZL-96036, BELL-CVE-2026-74546, DEBIAN-CVE-2026-74546, GHSA-x8wx-2r8m-399g, UBUNTU-CVE-2026-74546

## What is CVE-2026-74546?

CVE-2026-74546 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: (adt7470) Fix divide-by-zero TOCTOU crash in fan speed read

If the fan data becomes 0 between the FAN_DATA_VALID() check and the
FAN_PERIOD_TO_RPM() conversion, it will result in a divide-by-zero crash
due to a race with a concurrent update of the cached fan value.

Fix a TOCTOU issue by reading fan data once.

## Which versions are affected by CVE-2026-74546?


## How do I fix CVE-2026-74546?

Apply the vendor's patch.

## Is CVE-2026-74546 being exploited?

There is no known exploitation of CVE-2026-74546 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-74546 and fix it if it is affected.

What it is: CVE-2026-74546 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-2026-74546 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-2026-74546/ (Markdown: https://insights.sbomify.com/CVE-2026-74546/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-74546
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-74546
- OSV: https://osv.dev/vulnerability/CVE-2026-74546

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-74546/
Summaries are generated and may contain mistakes; the official description above is the record.