# CVE-2026-99124: s390/pci: Fix leak of uninitialized kernel data in SCLP report


- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 28 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** AZL-111230, BELL-CVE-2026-99124, DEBIAN-CVE-2026-99124, GHSA-7c6q-xh8w-h79r, UBUNTU-CVE-2026-99124

## What is CVE-2026-99124?

CVE-2026-99124 is a vulnerability in Linux, published on 28 Oct 2026. 

### Official description

In the Linux kernel, the following vulnerability has been resolved:

s390/pci: Fix leak of uninitialized kernel data in SCLP report

While report_error_write() checks that the provided buffer is at least
as large as the header struct, but not that it is large enough to
contain the report with the length claimed by report->length. If
user-space provides a short buffer, meaning a larger report->length than
the actually written payload, up to around 4K of kernel data from past
the kmalloc(len + 1) sized buffer allocated in kernfs_fop_write_iter()
will leak into the SCLP report.

However, as the entity processing the SCLP is privileged and able to
access at least the page including the report, this does not leak data
that entity could not access but it is still an out of bounds read and
a malformed error report that should be rejected.

## Which versions are affected by CVE-2026-99124?


## How do I fix CVE-2026-99124?

Upgrade to a fixed version.

## Is CVE-2026-99124 being exploited?

There is no known exploitation of CVE-2026-99124 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-99124 and fix it if it is affected.

What it is: CVE-2026-99124 is a vulnerability in Linux, published on 28 Oct 2026. 
Exploitation: There is no known exploitation of CVE-2026-99124 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-2026-99124/ (Markdown: https://insights.sbomify.com/CVE-2026-99124/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-99124
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-99124
- OSV: https://osv.dev/vulnerability/CVE-2026-99124

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-99124/
Summaries are generated and may contain mistakes; the official description above is the record.