# CVE-2026-98199: hwmon: (pmbus/core) increase number of phases and add new mask

> A buffer overflow in the Linux kernel PMBus driver allows local attackers to execute arbitrary code or escalate privileges via out-of-bounds writes.

- **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:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106284, BELL-CVE-2026-98199, DEBIAN-CVE-2026-98199, GHSA-9pcx-3cww-2wxv, UBUNTU-CVE-2026-98199

## What is CVE-2026-98199?

CVE-2026-98199 is a memory corruption 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: (pmbus/core) increase number of phases and add new mask

Increase the number of phases to 16 as a new upcoming device supports
such a number.

While at it, add a new mask for controlling the source of the output
voltage.

Note (groeck):

This patch was meant to prepare for support of MAX20826 and compatible
devices, which support more than 10 phases per page. However, Sashiko
reports that the mp2975 driver already supports up to 14 phases, and the
mp2856 driver supports up to 12 phases. This already has the potential for
out-of-bounds writes when probing the affected chips, making this patch a
bug fix.

## Which versions are affected by CVE-2026-98199?


## How do I fix CVE-2026-98199?

Apply the vendor's patch.

## Is CVE-2026-98199 being exploited?

There is no known exploitation of CVE-2026-98199 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98199 and fix it if it is affected.

What it is: CVE-2026-98199 is a memory corruption 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-2026-98199 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-2026-98199/ (Markdown: https://insights.sbomify.com/CVE-2026-98199/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98199
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98199
- OSV: https://osv.dev/vulnerability/CVE-2026-98199

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98199/
Summaries are generated and may contain mistakes; the official description above is the record.