CVE-2026-90401 — Kernel
HIGHCVE-2026-90401 is a high-severity (CVSS 7.1) vulnerability in Kernel. A fix is available for Kernel — see the affected versions and patch details below.
md: remove REQ_NOWAIT support from raid1/10/456
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-90401 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 376,715 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
KernelReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Linux packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐧Linux | Kernel | ≥ 5.17.0&&< 7.2.6 | 7.2.6 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for Kernel, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update Kernel to 7.2.6 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-90401 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-90401 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-90401. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-90401 in your dependencies?
O3 Security finds CVE-2026-90401 across Linux dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.