CVE-2025-38621

System crash via stale mddev pointer dereference

Published Aug 22, 2025 · Updated Sep 7, 2026

NULL pointer dereference in Linux kernel MD/RAID 6.7 through 6.16.0 allows local users to crash the system during array synchronization. In rdev_addable, an RCU read-side section keeps the RAID device alive but does not prevent md_kick_rdev_from_array from clearing rdev->mddev before the grace period ends. A low-privileged local user must reach MD synchronization on a system using the affected RAID code; the resulting kernel panic interrupts the host.

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

What happened

NULL pointer dereference in Linux kernel MD/RAID 6.7 through 6.16.0 allows local users to crash the system during array synchronization. In rdev_addable, an RCU read-side section keeps the RAID device alive but does not prevent md_kick_rdev_from_array from clearing rdev->mddev before the grace period ends. A low-privileged local user must reach MD synchronization on a system using the affected RAID code; the resulting kernel panic interrupts the host.

The record

CVE
CVE-2025-38621
Published
Aug 22, 2025
Updated
Sep 7, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 22, 2025CVE publishedPublication date reported by the CVE source.
  2. Sep 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=6.7
  2. Affected versionversion=bc08041b32abe6c9824f78735bac22018eabfc06 <13017b427118f4311471ee47df74872372ca8482
  3. Affected versionversion=bc08041b32abe6c9824f78735bac22018eabfc06 <b5fbe940862339cdcc34dea7a057ad18d18fa137
  4. Affected versionversion=bc08041b32abe6c9824f78735bac22018eabfc06 <d713e105a6137d3f54f09d4d9e2273482057ca17

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=6.7; version=bc08041b32abe6c9824f78735bac22018eabfc06 <13017b427118f4311471ee47df74872372ca8482; version=bc08041b32abe6c9824f78735bac22018eabfc06 <b5fbe940862339cdcc34dea7a057ad18d18fa137; version=bc08041b32abe6c9824f78735bac22018eabfc06 <d713e105a6137d3f54f09d4d9e2273482057ca17

Published CVSS scores

5.5NIST National Vulnerability DatabaseCVSS: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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 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.

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Technologies

Your stack

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Your stack

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