CVE-2026-43271

Kernel panic via startup race dereference

Published May 6, 2026 · Updated May 6, 2026

A NULL pointer dereference in Linux Kernel md-cluster allows local users to crash the system during clustered MD array startup. process_metadata_update() passes an unchecked mddev->thread pointer to wait_event() after the receive daemon starts but before the main MD thread is initialized. Exploitation requires local low-privileged access and a METADATA_UPDATED message from a cluster peer in the narrow startup window; the bounded impact is a kernel panic.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

A NULL pointer dereference in Linux Kernel md-cluster allows local users to crash the system during clustered MD array startup. process_metadata_update() passes an unchecked mddev->thread pointer to wait_event() after the receive daemon starts but before the main MD thread is initialized. Exploitation requires local low-privileged access and a METADATA_UPDATED message from a cluster peer in the narrow startup window; the bounded impact is a kernel panic.

The record

CVE
CVE-2026-43271
Published
May 6, 2026
Updated
May 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <721599e837d3f4c0e6cc14da059612c017b6d3ec
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dceb5a843910004cb118148e267036104fc3ee43
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dec123825c1ed74d98fd5fc7571a851dea4f46ff
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f150e753cb8dd756085f46e86f2c35ce472e0a3c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <721599e837d3f4c0e6cc14da059612c017b6d3ec; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <a61c1bc84c4a0f1e7c2fe55b0f43d7d94af4adf1; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dceb5a843910004cb118148e267036104fc3ee43; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <dec123825c1ed74d98fd5fc7571a851dea4f46ff; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f150e753cb8dd756085f46e86f2c35ce472e0a3c

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo