CVE-2026-90401

/// Technical 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

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References