---
id: CVE-2026-90401
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  md: remove REQ_NOWAIT support from raid1/10/456

  REQ_NOWAIT support in md personalities that can block internally is
  fundamentally incomplete
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  md: remove REQ_NOWAIT support from raid1/10/456

  REQ_NOWAIT support in md personalities that can block internally is
  fundamentally incomplete. While reads can avoid som…
severity: high
cvss: 7.1
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= f51d46d0e7cb5b8494aa534d276a9d8915a2443d <
    9bb9504e2d8f3d22ef12d51c333dd499f402dc8f
  - >-
    Linux >= f51d46d0e7cb5b8494aa534d276a9d8915a2443d <
    3fe5b7c9fb72ccc29bfd0f955b124892af7e3674
  - Linux 39db562b3fedb93978a7e42dd216b306740959f8
  - Linux >= 5.15.111 < 5.16
  - Linux 5.17
published: '2026-09-17'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T11:18:02.367'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90401'
references:
  - url: 'https://git.kernel.org/stable/c/3fe5b7c9fb72ccc29bfd0f955b124892af7e3674'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9bb9504e2d8f3d22ef12d51c333dd499f402dc8f'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ffcc9ea4e4d121c78aef6654a1577aa7d120774d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90401.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-90401'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2536659'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-90401'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-90401'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-90401.mbox
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00169
epssPercentile: 0.06237
ingestedAt: '2026-09-17T16:21:47.800Z'
cwe:
  - CWE-390
scores:
  nvd: 7.1
  vendor: 7
---

## Overview

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

md: remove REQ_NOWAIT support from raid1/10/456

REQ_NOWAIT support in md personalities that can block internally is
fundamentally incomplete. While reads can avoid some blocking paths,
write requests can still encounter cases where one mirror succeeds while
another returns -EAGAIN. At that point md cannot distinguish queue
pressure from a real device failure, so it can neither record a bad
block nor safely retry the write without REQ_NOWAIT, leaving mirrors
with divergent data.

Rather than continue advertising REQ_NOWAIT support for personalities
that cannot implement it correctly, remove it from raid1, raid10 and
raid456. Keep REQ_NOWAIT for linear and raid0, which only remap bios to
their underlying devices; stacked limits will still clear the feature if
any component device lacks REQ_NOWAIT support.

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, … · updated 2026-10-20 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90401.json)