# CVE-2026-89926: KVM: s390: Fix length check __import_wp_info()

> A local attacker can trigger a denial of service in the Linux kernel KVM s390 subsystem by exploiting an integer truncation flaw in length validation.

- **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:** 16 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-101370, BELL-CVE-2026-89926, DEBIAN-CVE-2026-89926, GHSA-2m53-w88c-rh92, UBUNTU-CVE-2026-89926

## What is CVE-2026-89926?

CVE-2026-89926 is a vulnerability in Linux, published on 16 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:

KVM: s390: Fix length check __import_wp_info()

struct kvm_hw_breakpoint::len is a __u64 that is fully controlled by user
space. This is then assigned to wp_info->len, which is an int. The bounds
check is done on the truncated value while the allocation uses the
untruncated one:

	wp_info->len = bp_data->len;
	[...]
	if (wp_info->len < 0 || wp_info->len > MAX_WP_SIZE)
		return -EINVAL;

	wp_info->old_data = kmalloc(bp_data->len, GFP_KERNEL_ACCOUNT);

Use the validated value for the allocation as intended. Without this
fix userspace can trigger >4GB allocations which will fail and result
in a WARN due to MAX_PAGE_ORDER.

## Which versions are affected by CVE-2026-89926?


## How do I fix CVE-2026-89926?

Apply the vendor's patch.

## Is CVE-2026-89926 being exploited?

There is no known exploitation of CVE-2026-89926 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89926 and fix it if it is affected.

What it is: CVE-2026-89926 is a vulnerability in Linux, published on 16 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-2026-89926 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-2026-89926/ (Markdown: https://insights.sbomify.com/CVE-2026-89926/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89926
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89926
- OSV: https://osv.dev/vulnerability/CVE-2026-89926

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89926/
Summaries are generated and may contain mistakes; the official description above is the record.