# CVE-2026-89978: accel/amdxdna: return early from a zero-length flush

> A local attacker with access to the AMD XDNA render node can trigger a kernel page fault and crash the system by issuing a zero-length flush request.

- **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:** BELL-CVE-2026-89978, DEBIAN-CVE-2026-89978, GHSA-3x6j-vqfr-gqqm, UBUNTU-CVE-2026-89978

## What is CVE-2026-89978?

CVE-2026-89978 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:

accel/amdxdna: return early from a zero-length flush

SYNC_BO does not constrain its size, so a request for zero bytes reaches
drm_clflush_virt_range(), which ends with an unconditional
clflushopt(end - 1). For an empty range that is the byte before the
mapping, and abo->mem.kva comes from vmap(), so the access lands in the
guard page below the vmalloc area and faults:

  BUG: unable to handle page fault for address: ffffd16fbbc70fff
  #PF: supervisor read access in kernel mode
  Oops: Oops: 0000 [#1] SMP NOPTI
  CPU: 7 UID: 1000 Comm: sync_bo_probe
  RIP: 0010:drm_clflush_virt_range+0x3c/0x70
  Call Trace:
   amdxdna_drm_sync_bo_ioctl+0x124/0x430 [amdxdna]
   drm_ioctl+0x301/0x4c0
   __x64_sys_ioctl+0x115/0x2f0
   do_syscall_64+0xa6/0x3d0

Any process that can open the render node can do this. Reproduced 3 of 3
times on a Strix Point NPU (1022:17f0), by calling SYNC_BO with size 0 on
an AMDXDNA_BO_SHARE object. The import arm takes the same request but
flushes the whole scatterlist, so it survives it.

Nothing needs flushing for an empty range, so answer before choosing a
path.

## Which versions are affected by CVE-2026-89978?


## How do I fix CVE-2026-89978?

Apply the vendor's patch.

## Is CVE-2026-89978 being exploited?

There is no known exploitation of CVE-2026-89978 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89978 and fix it if it is affected.

What it is: CVE-2026-89978 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-2026-89978 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-2026-89978/ (Markdown: https://insights.sbomify.com/CVE-2026-89978/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89978
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89978
- OSV: https://osv.dev/vulnerability/CVE-2026-89978

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89978/
Summaries are generated and may contain mistakes; the official description above is the record.