# CVE-2026-98475: s390/cmf: Fix virtual vs physical address confusion

> A kernel flaw allows firmware to use incorrect addresses for channel measurement data, potentially leading to memory corruption or data exposure on s390 systems.

- **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:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-98475, DEBIAN-CVE-2026-98475, GHSA-p4wm-c7q2-mpq9, UBUNTU-CVE-2026-98475

## What is CVE-2026-98475?

CVE-2026-98475 is a memory corruption vulnerability in Linux, published on 18 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:

s390/cmf: Fix virtual vs physical address confusion

The measurement block address is an absolute address. Define the
associated schib_config and schib fields as dma64_t to enable automatic
detection of incorrect assignments. Also add the missing virt_to_dma64()
translation.

Without this fix, a wrong address will be used by firmware when storing
extended format channel measurement data on kernels built with
CONFIG_RANDOMIZE_IDENTITY_BASE=y.

## Which versions are affected by CVE-2026-98475?


## How do I fix CVE-2026-98475?

Apply the vendor's patch.

## Is CVE-2026-98475 being exploited?

There is no known exploitation of CVE-2026-98475 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98475 and fix it if it is affected.

What it is: CVE-2026-98475 is a memory corruption vulnerability in Linux, published on 18 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-2026-98475 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-2026-98475/ (Markdown: https://insights.sbomify.com/CVE-2026-98475/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98475
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98475
- OSV: https://osv.dev/vulnerability/CVE-2026-98475

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98475/
Summaries are generated and may contain mistakes; the official description above is the record.