CVE-2026-90401

md: remove REQ_NOWAIT support from raid1/10/456

Published Sep 17, 2026 CVSS 3.1 · 7.1 High EPSS < 1% KEV · Not listed
Description
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

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-9019-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-9020-1 Linux kernel vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-362
CWE-665
Type Values Removed Values Added
Weaknesses CWE-390
Type Values Removed Values Added
Weaknesses CWE-390
Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.1, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H'}

Type Values Removed Values Added
Description 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.
Title md: remove REQ_NOWAIT support from raid1/10/456
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 19, 2026, 9:03 AM
Reserved
Sep 11, 2026, 7:38 PM
Status
Received
Published
Sep 17, 2026, 5:17 PM
Modified
Oct 19, 2026, 9:19 AM