# CVE-2026-97989: vduse: validate virtqueue alignment

> A missing validation in the Linux kernel's vduse driver allows a local attacker to trigger a null pointer dereference and system crash by configuring invalid virtqueue alignment.

- **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 Sep 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-104751, BELL-CVE-2026-97989, DEBIAN-CVE-2026-97989, GHSA-fgw5-49qv-38cm, UBUNTU-CVE-2026-97989

## What is CVE-2026-97989?

CVE-2026-97989 is a vulnerability in Linux, published on 25 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:

vduse: validate virtqueue alignment

vduse_validate_config() only checks the upper bound of vq_align. Invalid
values can therefore reach vring_create_virtqueue_map(). The split-ring
helpers use align - 1 as a bit mask, so the alignment must be a non-zero
power of two. A zero value makes vring_size() drop the descriptor and
available-ring part and vring_init() leave the used ring pointer NULL.

The VIRTIO spec requires the used ring to start at an address
aligned to at least 4 bytes. Reject values below VRING_USED_ALIGN_SIZE as
well as non-power-of-two values before they reach the virtio ring helpers.

Opening a virtio-net device created with vq_align=0 triggered:

BUG: KASAN: null-ptr-deref in virtqueue_kick_prepare_split+0xe3/0x100
Read of size 2 at addr 0000000000000000 by task systemd-network/1062

Call Trace (relevant frames):
 dump_stack_lvl
 print_report
 kasan_report
 __asan_load2
 virtqueue_kick_prepare_split+0xe3/0x100
 virtqueue_kick_prepare+0x40/0x60
 try_fill_recv+0x857/0x1250
 virtnet_open+0x189/0x460
 __dev_open+0x225/0x390
 __dev_change_flags+0x368/0x3b0
 netif_change_flags+0x56/0xc0
 do_setlink.isra.0+0x68c/0x1e30

Validate the value before it reaches the virtio ring helpers.

## Which versions are affected by CVE-2026-97989?


## How do I fix CVE-2026-97989?

Apply the vendor's patch.

## Is CVE-2026-97989 being exploited?

There is no known exploitation of CVE-2026-97989 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-97989 and fix it if it is affected.

What it is: CVE-2026-97989 is a vulnerability in Linux, published on 25 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-2026-97989 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-2026-97989/ (Markdown: https://insights.sbomify.com/CVE-2026-97989/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-97989
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-97989
- OSV: https://osv.dev/vulnerability/CVE-2026-97989

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-97989/
Summaries are generated and may contain mistakes; the official description above is the record.