# CVE-2026-98471: KVM: SEV: Do cache maintenance on the source VM during intra-host migration

> A local attacker with high privileges can read stale data from CPU caches during KVM SEV intra-host migration due to missing cache maintenance on the source VM.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 24 Oct 2026
- **Also known as:** AZL-108702, BELL-CVE-2026-98471, DEBIAN-CVE-2026-98471, GHSA-hqmw-j6g2-75m9, UBUNTU-CVE-2026-98471

## What is CVE-2026-98471?

CVE-2026-98471 is a high-severity 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: SEV: Do cache maintenance on the source VM during intra-host migration

Manually perform cache maintenance on the source VM during intra-host
migration to ensure no stale data is left in CPU caches after the VM is
destroyed.  Because the source VM is "converted" to a non-SEV VM, KVM's
memory reclaim flows won't trigger cache maintenance, e.g. when all guest
memory is reclaimed in response to detaching from the mmu_notifier.

Note, relying on the destination VM to do cache maintenance isn't an option
as KVM doesn't require identical guest memory configurations, i.e. the
source VM may have access to memory that the destination VM does not.
Enforcing equivalent memory configurations is infeasible, as it would
require a *deep* comparison of memslots, e.g. to verify that not only are
the memslot identical, but what the memslots point at is also identical.

## Which versions are affected by CVE-2026-98471?


## How do I fix CVE-2026-98471?

Apply the vendor's patch.

## Is CVE-2026-98471 being exploited?

There is no known exploitation of CVE-2026-98471 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98471 and fix it if it is affected.

What it is: CVE-2026-98471 is a high-severity 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-2026-98471 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-2026-98471/ (Markdown: https://insights.sbomify.com/CVE-2026-98471/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98471
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98471
- OSV: https://osv.dev/vulnerability/CVE-2026-98471

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98471/
Summaries are generated and may contain mistakes; the official description above is the record.