---
id: CVE-2021-46969
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bus: mhi: core: Fix invalid error returning in mhi_queue

  mhi_queue returns an error when the doorbell is not accessible in
  the current state
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bus: mhi: core: Fix invalid error returning in mhi_queue

  mhi_queue returns an error when the doorbell is not accessible in
  the current state. This can happen when the …
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-416
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.12, < 5.12.3'
patched:
  - linux_kernel 5.12.3
published: '2024-02-27'
updated: '2026-08-04'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2021-46969'
references:
  - url: 'https://git.kernel.org/stable/c/0ecc1c70dcd32c0f081b173a1a5d89952686f271'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a99b661c3187365f81026d89b1133a76cd2652b3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/0ecc1c70dcd32c0f081b173a1a5d89952686f271'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: 'https://git.kernel.org/stable/c/a99b661c3187365f81026d89b1133a76cd2652b3'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00216
epssPercentile: 0.10757
ingestedAt: '2026-08-04T10:39:38.645Z'
---

## Overview

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

bus: mhi: core: Fix invalid error returning in mhi_queue

mhi_queue returns an error when the doorbell is not accessible in
the current state. This can happen when the device is in non M0
state, like M3, and needs to be waken-up prior ringing the DB. This
case is managed earlier by triggering an asynchronous M3 exit via
controller resume/suspend callbacks, that in turn will cause M0
transition and DB update.

So, since it's not an error but just delaying of doorbell update, there
is no reason to return an error.

This also fixes a use after free error for skb case, indeed a caller
queuing skb will try to free the skb if the queueing fails, but in
that case queueing has been done.

## Affected

- `linux_kernel >= 5.12, < 5.12.3`

## Remediation

Upgrade past the affected range:

- `linux_kernel 5.12.3`