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Linux KernelOperating system · Linux

CVE-2026-53123

MEDIUM · 5.5 CVSS v3.1 Published 2026-06-24
Fix available
A fix is available. Upgrade to 6.12.91 / 6.18.33 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: md: wake raid456 reshape waiters before suspend During raid456 reshape, direct IO across the reshape position can sleep in raid5_make_request() waiting for reshape progress while still holding an active_io reference. If userspace then freezes reshape and writes md/suspend_lo or md/suspend_hi, mddev_suspend() kills active_io and waits for all in-flight IO to drain. This can deadlock: the IO needs reshape progress to continue, but the reshape thread is already frozen, so the active_io reference is never dropped and suspend never completes. raid5_prepare_suspend() already wakes wait_for_reshape for dm-raid. Do the same for normal md suspend when reshape is already interrupted, so waiting raid456 IO can abort, drop its reference, and let suspend finish. The mdadm test tests/25raid456-reshape-deadlock reproduces the hang.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A deadlock vulnerability in Linux kernel's MD RAID456 implementation where direct I/O can block waiting for reshape progress while holding an active_io reference. If userspace then suspends the reshape via md/suspend_lo or md/suspend_hi, the I/O cannot complete (reshape frozen) and cannot release its reference, causing suspend to hang indefinitely.

MitigationApply the kernel patch that wakes raid456 reshape waiters before suspend (similar to existing dm-raid handling), allowing waiting I/O to abort and release its reference so suspend can complete.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 6.7, < 6.12.91>= 6.13, < 6.18.33>= 6.19, < 7.0.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify your kernel version
    Run `uname -r` or check `/proc/version` to get the exact kernel version number
    Affected if The version falls within >= 6.7, < 6.12.91 OR >= 6.13, < 6.18.33 OR >= 6.19, < 7.0.10
  2. Check if md raid456 arrays exist
    Examine `/proc/mdstat` or list `/sys/block/md*/md/` to see if any RAID 4/5/6 (raid456) arrays are configured
    Affected if Any raid456 arrays are present and active
  3. Verify if reshape operations are in progress
    Look at `/proc/mdstat` for lines containing 'reshape' or check `cat /sys/block/md*/md/reshape_position`
    Affected if A reshape operation is currently active on any raid456 array
  4. Check for direct IO usage on the array
    Monitor I/O patterns or check application configs for O_DIRECT flag usage when accessing devices in /proc/mdstat
    Affected if Direct IO is being performed against the raid456 array during reshape

You are affected if your kernel version is in the vulnerable range AND you have an active raid456 array undergoing reshape with direct IO traffic while suspend parameters (md/suspend_lo or md/suspend_hi) are in use.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.12.91 / 6.18.33 / 7.0.10 or later
Fixed in 6.12.916.18.337.0.10
Vendor patch git.kernel.org →
Interim mitigation

Apply the kernel patch that wakes raid456 reshape waiters before suspend (similar to existing dm-raid handling), allowing waiting I/O to abort and release its reference so suspend can complete.

Recommended fix High confidence

7.0.10 (or 6.12.91/6.18.33 depending on preferred stable branch)

  1. Identify the currently running Linux kernel version using 'uname -r'
  2. Determine which affected version range your current kernel falls into (6.7-6.12.x, 6.13-6.18.x, or 6.19-7.0.x)
  3. Upgrade the Linux kernel to a fixed version: 6.12.91 or later for 6.12.x branch, 6.18.33 or later for 6.18.x branch, or 7.0.10 or later for 7.0.x branch
  4. Reboot the system to load the new kernel
  5. Verify the kernel version after reboot using 'uname -r'
Caveat Kernel upgrades may require recompilation of proprietary kernel modules; ensure compatibility with installed drivers and software

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-53123 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data