---
id: CVE-2026-64017
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  blk-mq: pop cached request if it is usable

  When submitting a bio to blk-mq, if the task should sleep after peeking
  a cached request, but before it pops it, the plug fl…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  blk-mq: pop cached request if it is usable

  When submitting a bio to blk-mq, if the task should sleep after peeking
  a cached request, but before it pops it, the plug fl…
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 >= 6.1.72, < 6.2'
  - 'linux_kernel >= 6.1.75, < 6.2'
  - 'linux_kernel >= 6.5.13, < 6.6'
  - 'linux_kernel >= 6.6.3, < 6.7'
  - 'linux_kernel >= 6.6.14, < 6.7'
  - 'linux_kernel >= 6.7.1, < 6.12.104'
  - 'linux_kernel >= 6.13, < 6.18.45'
  - 'linux_kernel >= 6.19, < 7.0.11'
  - linux_kernel = 6.7
  - linux_kernel = 7.1
patched:
  - linux_kernel 7.0.11
published: '2026-07-19'
updated: '2026-10-13'
sourceUpdated: '2026-10-13T14:48:58.263'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64017'
references:
  - url: 'https://git.kernel.org/stable/c/23d8ea1e303b5f32d883757a4a707e791dbc9808'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/388468f7e7d1eab092cf2a39fdfb502e52019ec6'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/97e2d08de282ef76f84ab4ccd00f1acb3f5f999e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dc278e9bf2b9513a763353e6b9cc21e0f532954e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00125
epssPercentile: 0.01972
ingestedAt: '2026-10-13T15:33:40.022Z'
---

## Overview

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

blk-mq: pop cached request if it is usable

When submitting a bio to blk-mq, if the task should sleep after peeking
a cached request, but before it pops it, the plug flushes and calls
blk_mq_free_plug_rqs, freeing the cached_rqs. This creates a
use-after-free bug. Fix this by popping the cached request before any
possible blocking calls if it is suitable for use.

Popping this request first holds a queue reference, so avoid any
serialization races with queue freezes and can safely proceed with
dispatching that request to the driver. This potentially increases a
timing window from when a driver wants to freeze its queue to when
requests stop being dispatched. That scenario is off the fast path
though, and drivers need to appropriately handle requests during a
freeze request anyway.

The downside is the popped element needs to be individually freed when
we performed a bio plug merge. The cached request would have had to be
freed later anyway, but this patch does it inline with building the plug
list instead of after flushing it.

## Affected

- `linux_kernel >= 6.1.72, < 6.2`
- `linux_kernel >= 6.1.75, < 6.2`
- `linux_kernel >= 6.5.13, < 6.6`
- `linux_kernel >= 6.6.3, < 6.7`
- `linux_kernel >= 6.6.14, < 6.7`
- `linux_kernel >= 6.7.1, < 6.12.104`
- `linux_kernel >= 6.13, < 6.18.45`
- `linux_kernel >= 6.19, < 7.0.11`
- `linux_kernel = 6.7`
- `linux_kernel = 7.1`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.0.11`