# CVE-2026-89936: iio: dac: m62332: Fix regulator reference count imbalance

> A reference count imbalance in the m62332 DAC driver allows local attackers to keep regulators enabled indefinitely, potentially causing resource exhaustion.

- **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:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101481, BELL-CVE-2026-89936, DEBIAN-CVE-2026-89936, GHSA-93hj-782q-v32m, UBUNTU-CVE-2026-89936

## What is CVE-2026-89936?

CVE-2026-89936 is a denial of service vulnerability in Linux, published on 16 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:

iio: dac: m62332: Fix regulator reference count imbalance

m62332_set_value() enables the Vcc regulator on every write of a
non-zero value and disables it on every write of zero, without tracking
the channel's current state. Because the regulator is reference counted,
changing a channel directly from one non-zero value to another enables
it more than once, while a later write of zero disables it only once.
The reference count never returns to zero and the regulator is left
enabled indefinitely.

Only enable the regulator on the transition from zero to non-zero, and
only disable it on the transition from non-zero to zero, using the
previously stored channel value to detect the edge. Balance the
regulator on the I2C error path so the reference count stays consistent
if the write fails.

## Which versions are affected by CVE-2026-89936?


## How do I fix CVE-2026-89936?

Apply the vendor's patch.

## Is CVE-2026-89936 being exploited?

There is no known exploitation of CVE-2026-89936 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89936 and fix it if it is affected.

What it is: CVE-2026-89936 is a denial of service vulnerability in Linux, published on 16 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-2026-89936 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-2026-89936/ (Markdown: https://insights.sbomify.com/CVE-2026-89936/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89936
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89936
- OSV: https://osv.dev/vulnerability/CVE-2026-89936

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89936/
Summaries are generated and may contain mistakes; the official description above is the record.