# CVE-2026-80870: drm/amdkfd: Validate CRIU-restored IDs before idr_alloc

> A local attacker can trigger a kernel warning and potential system crash by providing invalid IDs during CRIU restore operations in the AMD KFD driver.

- **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:** 4 Sep 2026
- **Updated:** 4 Sep 2026
- **Also known as:** BELL-CVE-2026-80870, DEBIAN-CVE-2026-80870, GHSA-3fvv-ffr9-f4xf, UBUNTU-CVE-2026-80870

## What is CVE-2026-80870?

CVE-2026-80870 is a denial of service vulnerability in Linux, published on 4 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:

drm/amdkfd: Validate CRIU-restored IDs before idr_alloc

The KFD CRIU restore flow restores previously saved object IDs from
userspace.

For event restore:

  kfd_criu_restore_event()
      -> create_signal_event() / create_other_event()
          -> allocate_event_notification_slot()
              -> idr_alloc(..., *restore_id, *restore_id + 1, ...)

For BO restore:

  criu_restore_memory_of_gpu()
      -> idr_alloc(..., bo_priv->idr_handle, ...)

In both cases, the restored ID comes from userspace-provided CRIU data.

idr_alloc() expects the ID range values to fit within signed int
limits. If a restored ID is larger than INT_MAX, it can trigger a WARN
in the IDR layer.

A kernel WARN is undesirable because it prints a warning trace and may
cause a panic or reboot on systems with panic_on_warn enabled.

Smatch reported these paths as allowing unchecked userspace values to
reach idr_alloc().

Add INT_MAX validation before using restored IDs in:

- kfd_criu_restore_event()
- criu_restore_memory_of_gpu()

If the restored ID is invalid, return -EINVAL.

This prevents invalid restore data from reaching the IDR layer and
avoids WARN-triggering paths, while keeping valid restore behavior
unchanged.

## Which versions are affected by CVE-2026-80870?


## How do I fix CVE-2026-80870?

Apply the vendor's patch.

## Is CVE-2026-80870 being exploited?

There is no known exploitation of CVE-2026-80870 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80870 and fix it if it is affected.

What it is: CVE-2026-80870 is a denial of service vulnerability in Linux, published on 4 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-2026-80870 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-2026-80870/ (Markdown: https://insights.sbomify.com/CVE-2026-80870/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80870
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80870
- OSV: https://osv.dev/vulnerability/CVE-2026-80870

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80870/
Summaries are generated and may contain mistakes; the official description above is the record.