# CVE-2026-64474: vfio: prevent infinite loop in vfio_mig_get_next_state() on blocked arc

> A local attacker can trigger an infinite loop in the Linux kernel VFIO migration code, causing a system hang or panic.

- **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:** 25 Jul 2026
- **Updated:** 17 Aug 2026
- **Also known as:** AZL-93764, BELL-CVE-2026-64474, DEBIAN-CVE-2026-64474, GHSA-67fj-9v49-3ch9, ROOT-OS-UBUNTU-2204-CVE-2026-64474, UBUNTU-CVE-2026-64474

## What is CVE-2026-64474?

CVE-2026-64474 is a denial of service vulnerability in Linux, published on 25 Jul 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:

vfio: prevent infinite loop in vfio_mig_get_next_state() on blocked arc

vfio_mig_get_next_state() walks vfio_from_fsm_table[] one step at a time,
looping to skip optional states the device does not support until
*next_fsm is supported. A blocked transition is encoded as
VFIO_DEVICE_STATE_ERROR, which the trailing return reports as -EINVAL.

The skip loop does not account for the ERROR sentinel.
state_flags_table[ERROR] is ~0U and vfio_from_fsm_table[ERROR][*] is
ERROR, so once *next_fsm becomes ERROR the loop condition stays true and
*next_fsm never changes. The blocked arcs STOP_COPY -> PRE_COPY and
STOP_COPY -> PRE_COPY_P2P map to ERROR yet pass the support check on a
precopy-capable device, causing the loop to spin forever while holding
the driver state mutex. This can result in a soft lockup, and a panic
with softlockup_panic set.

Terminate the skip loop on the ERROR sentinel so a blocked transition
falls through to the existing return and reports -EINVAL.

## Which versions are affected by CVE-2026-64474?


## How do I fix CVE-2026-64474?

Apply the vendor's patch.

## Is CVE-2026-64474 being exploited?

There is no known exploitation of CVE-2026-64474 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-64474 and fix it if it is affected.

What it is: CVE-2026-64474 is a denial of service vulnerability in Linux, published on 25 Jul 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-2026-64474 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-2026-64474/ (Markdown: https://insights.sbomify.com/CVE-2026-64474/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-64474
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-64474
- OSV: https://osv.dev/vulnerability/CVE-2026-64474

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-64474/
Summaries are generated and may contain mistakes; the official description above is the record.