# CVE-2026-63936: iio: adc: mt6359: fix unchecked return value in mt6358_read_imp

> An attacker with local access can read uninitialized stack memory via the mt6359 ADC driver, potentially leaking sensitive kernel data.

- **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:** 19 Jul 2026
- **Updated:** 19 Jul 2026
- **Also known as:** BELL-CVE-2026-63936, DEBIAN-CVE-2026-63936, GHSA-856p-gwqh-fxcq, UBUNTU-CVE-2026-63936

## What is CVE-2026-63936?

CVE-2026-63936 is a vulnerability in Linux, published on 19 Jul 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:

iio: adc: mt6359: fix unchecked return value in mt6358_read_imp

In mt6358_read_imp(), the variable val_v is passed to regmap_read()
but the return value is not checked. If the read fails, val_v remains
uninitialized and its random stack content is subsequently reported
as a measurement result.

Initialize val_v to zero to ensure a predictable value is reported
in case of bus failure and to prevent potential stack data leakage.
This also satisfies static analyzers that might otherwise flag the
variable as used uninitialized.

## Which versions are affected by CVE-2026-63936?


## How do I fix CVE-2026-63936?

Apply the vendor's patch.

## Is CVE-2026-63936 being exploited?

There is no known exploitation of CVE-2026-63936 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63936 and fix it if it is affected.

What it is: CVE-2026-63936 is a vulnerability in Linux, published on 19 Jul 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-2026-63936 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-2026-63936/ (Markdown: https://insights.sbomify.com/CVE-2026-63936/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63936
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63936
- OSV: https://osv.dev/vulnerability/CVE-2026-63936

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63936/
Summaries are generated and may contain mistakes; the official description above is the record.