# CVE-2026-98637: KVM: arm64: Do not clear VM-wide SVE feature on vCPU init failure

> A null pointer dereference in KVM arm64 allows a local attacker to cause a denial of service by triggering a guest floating-point access after a failed vCPU initialization.

- **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:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-98637, DEBIAN-CVE-2026-98637, GHSA-j9wj-wgv2-phcm, UBUNTU-CVE-2026-98637

## What is CVE-2026-98637?

CVE-2026-98637 is a vulnerability in Linux, published on 18 Oct 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: arm64: Do not clear VM-wide SVE feature on vCPU init failure

pkvm_vcpu_init_sve() clears KVM_ARM_VCPU_SVE in kvm->arch.vcpu_features
when it fails, but vcpu_has_sve() tests KVM_ARCH_FLAG_GUEST_HAS_SVE,
which is left set. Later vCPUs on that VM then skip the SVE setup and
register with a NULL sve_state, which the guest's first FP access hands
to sve_load_state().

Return the error without touching vcpu_features.

## Which versions are affected by CVE-2026-98637?


## How do I fix CVE-2026-98637?

Apply the vendor's patch.

## Is CVE-2026-98637 being exploited?

There is no known exploitation of CVE-2026-98637 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98637 and fix it if it is affected.

What it is: CVE-2026-98637 is a vulnerability in Linux, published on 18 Oct 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-2026-98637 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-2026-98637/ (Markdown: https://insights.sbomify.com/CVE-2026-98637/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98637
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98637
- OSV: https://osv.dev/vulnerability/CVE-2026-98637

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98637/
Summaries are generated and may contain mistakes; the official description above is the record.