# CVE-2026-72236: s390/perf_cpum_cf: Add missing array_index_nospec() to __hw_perf_event_init()

> A missing speculation barrier in the Linux kernel s390 perf driver allows local attackers to potentially read sensitive memory via speculative execution.

- **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:** 15 Aug 2026
- **Updated:** 23 Aug 2026
- **Also known as:** BELL-CVE-2026-72236, DEBIAN-CVE-2026-72236, GHSA-54pj-2wqr-j294, UBUNTU-CVE-2026-72236

## What is CVE-2026-72236?

CVE-2026-72236 is a vulnerability in Linux, published on 15 Aug 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/perf_cpum_cf: Add missing array_index_nospec() to __hw_perf_event_init()

ev variable is userspace controlled via event->attr.config and used
as an array index after bounds checking, but without speculation
barriers.

Add the missing array_index_nospec() call to prevent speculative
execution.

## Which versions are affected by CVE-2026-72236?


## How do I fix CVE-2026-72236?

Apply the vendor's patch.

## Is CVE-2026-72236 being exploited?

There is no known exploitation of CVE-2026-72236 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72236 and fix it if it is affected.

What it is: CVE-2026-72236 is a vulnerability in Linux, published on 15 Aug 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-2026-72236 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-2026-72236/ (Markdown: https://insights.sbomify.com/CVE-2026-72236/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72236
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72236
- OSV: https://osv.dev/vulnerability/CVE-2026-72236

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72236/
Summaries are generated and may contain mistakes; the official description above is the record.