---
id: CVE-2026-97994
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  vhost/vdpa: reject VRING_NUM larger than device max

  vhost_vring_set_num() accepts any non-zero power-of-two queue size that
  fits in 16 bits
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  vhost/vdpa: reject VRING_NUM larger than device max

  vhost_vring_set_num() accepts any non-zero power-of-two queue size that
  fits in 16 bits. vhost-vdpa then passes tha…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 4c8cf31885f69e86be0b5b9e6677a26797365e1d <
    1d09201d81b7d3e276860cc7b7dbf6c6cbe8e9b4
  - >-
    Linux >= 4c8cf31885f69e86be0b5b9e6677a26797365e1d <
    68232102f20fc961327fb9e0f605a7eaadf030a9
  - >-
    Linux >= 4c8cf31885f69e86be0b5b9e6677a26797365e1d <
    59522639a7d71cff4e20d594d0b9ea30dd0c77e0
  - >-
    Linux >= 4c8cf31885f69e86be0b5b9e6677a26797365e1d <
    ccb1dc7c527f8c925925cf92afc76ae590dac311
  - Linux 5.7
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T11:17:27.637'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-97994'
references:
  - url: 'https://git.kernel.org/stable/c/1d09201d81b7d3e276860cc7b7dbf6c6cbe8e9b4'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/59522639a7d71cff4e20d594d0b9ea30dd0c77e0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/68232102f20fc961327fb9e0f605a7eaadf030a9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ccb1dc7c527f8c925925cf92afc76ae590dac311'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.864Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

vhost/vdpa: reject VRING_NUM larger than device max

vhost_vring_set_num() accepts any non-zero power-of-two queue size that
fits in 16 bits. vhost-vdpa then passes that value to set_vq_num()
without comparing it with get_vq_num_max().

A process with access to /dev/vhost-vdpa-* can therefore configure a
queue larger than the device advertises. With vdpa_sim, the worker can
walk descriptors beyond the mapped descriptor ring. KASAN reports a
16-byte out-of-bounds read, corresponding to one vring_desc, in the
vringh IOTLB path:

  BUG: KASAN: out-of-bounds in _copy_from_iter
  Read of size 16
  copy_from_iotlb
  copydesc_iotlb
  vringh_getdesc_iotlb
  vdpasim_net_work

Cache get_vq_num_max() immediately after reset. Some backends derive
it from writable queue-size state, so querying it after SET_NUM may
return the current size instead of the device capability. Invalidate
the cached value before reset so a failed reset leaves SET_NUM
disabled.

For VHOST_SET_VRING_NUM, copy the complete vring state once and use
the same index and size for validation, vq->num, and set_vq_num().
This ensures that validation and use operate on the same copied values.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.