# CVE-2026-97591: s390/crypto: Fix handling of EBUSY in PHMAC when req is pushed to crypto engine

> A missing EBUSY handling in the s390 PHMAC crypto driver can cause denial of service when requests are pushed to the crypto engine.

- **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:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-97591, DEBIAN-CVE-2026-97591, GHSA-48x9-wv7p-5368, UBUNTU-CVE-2026-97591

## What is CVE-2026-97591?

CVE-2026-97591 is a denial of service vulnerability in Linux, published on 25 Sep 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/crypto: Fix handling of EBUSY in PHMAC when req is pushed to crypto engine

When a request is transferred to the engine via
crypto_transfer_hash_request_to_engine() there are two return codes
signaling a successful transfer: EINPROGRESS and EBUSY. However the
correct handling of EBUSY was missing and has been added as a return
code indicating a successful transfer to the crypto engine.

## Which versions are affected by CVE-2026-97591?


## How do I fix CVE-2026-97591?

Apply the vendor's patch.

## Is CVE-2026-97591 being exploited?

There is no known exploitation of CVE-2026-97591 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97591 and fix it if it is affected.

What it is: CVE-2026-97591 is a denial of service vulnerability in Linux, published on 25 Sep 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-2026-97591 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-2026-97591/ (Markdown: https://insights.sbomify.com/CVE-2026-97591/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97591
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97591
- OSV: https://osv.dev/vulnerability/CVE-2026-97591

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97591/
Summaries are generated and may contain mistakes; the official description above is the record.