# CVE-2026-31482: s390/entry: Scrub r12 register on kernel entry

> An attacker could potentially read sensitive kernel memory via the unscrubbed r12 register on s390 architecture due to missing register clearing.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** 22 Apr 2026
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2026-31482, DEBIAN-CVE-2026-31482, GHSA-2rvp-wpqf-89pf, ROOT-OS-DEBIAN-13-CVE-2026-31482, ROOT-OS-UBUNTU-2404-CVE-2026-31482, UBUNTU-CVE-2026-31482

## What is CVE-2026-31482?

CVE-2026-31482 is a medium-severity vulnerability in Linux kernel, published on 22 Apr 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/entry: Scrub r12 register on kernel entry

Before commit f33f2d4c7c80 ("s390/bp: remove TIF_ISOLATE_BP"),
all entry handlers loaded r12 with the current task pointer
(lg %r12,__LC_CURRENT) for use by the BPENTER/BPEXIT macros. That
commit removed TIF_ISOLATE_BP, dropping both the branch prediction
macros and the r12 load, but did not add r12 to the register clearing
sequence.

Add the missing xgr %r12,%r12 to make the register scrub consistent
across all entry points.

## Which versions are affected by CVE-2026-31482?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31482?

Apply the vendor's patch.

## Is CVE-2026-31482 being exploited?

There is no known exploitation of CVE-2026-31482 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-31482 and fix it if it is affected.

What it is: CVE-2026-31482 is a medium-severity vulnerability in Linux kernel, published on 22 Apr 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-2026-31482 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2026-31482/ (Markdown: https://insights.sbomify.com/CVE-2026-31482/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31482
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31482
- OSV: https://osv.dev/vulnerability/CVE-2026-31482

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31482/
Summaries are generated and may contain mistakes; the official description above is the record.