[CVE-2026-53125][LOW] md: fix array_state=clear sysfs deadlock [ Upstream

[CVE-2026-53125][LOW] md: fix array_state=clear sysfs deadlock [ Upstream

[AL-KERNEL]

CVE: CVE-2026-53125
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: md: fix array_state=clear sysfs deadlock [ Upstream
Commit: 62c44566da7493ee48ef17e8507bb798338a07cb
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=62c44566da7493ee48ef17e8507bb798338a07cb
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53125
Analysis date: Wed, 24 Jun 2026 14:05:58 -0400
ActionableScore: 2
ActionableScore lower bound: 0
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A local privileged or delegated storage-management user can trigger a sysfs/kernfs deadlock by clearing an MD array state during teardown, causing a denial of service without evidence of memory corruption or privilege escalation.

======================================================================
ABOUT THIS REPORT
======================================================================

The original Linux kernel CVE announcement for CVE-2026-53125 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53125

The original announcement does not normally provide a security severity
estimate, CVSS assessment, or enough information to determine whether the
reported kernel bug represents a practically relevant security issue.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin. It combines
an autonomous classifier with LLM-assisted technical analysis and a
separate ActionableScore mechanism.

The purpose of this report is to prioritize Linux kernel CVEs before
manual review, identify cases that require prompt investigation, and
support automatic closure of issues that are unlikely to have meaningful
security impact.

Published priority for this report: LOW
Manual review required: NO

A detailed explanation of the methodology and priority rules is included
at the end of this message.

======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-53125	LOW	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-667;*CWE-833;*CWE-664;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.5';DESCR 'md array_state clear can hit a sysfs and kernfs deadlock because md_attr_store() may drop the mddev reference before restoring sysfs active protection. If the temporary kobject reference from sysfs_break_active_protection() becomes the last reference, sysfs_unbreak_active_protection() can trigger md kobject teardown from the current sysfs writer context while the same sysfs node is still being unwound. For the CVSS the PR:L is used for the paranoid score because a reduced capability storage management process or delegated admin context may be able to write the md sysfs control file, while normal systems usually require full admin privileges. The issue is not network reachable and requires local control of md sysfs state. Impact is denial of service through recursive kernfs locking or a stuck sysfs write path, with no supported confidentiality or integrity impact.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 1) 	MAYBE	LOCK DEADLOCK DISK WARNONLY LINUS  INCREASED_FROM_LOW_BASED_ON_HIGHCVSSSCORE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=2
ActionableScoreLower=0

## 1. ActionableScore

* Conservative score: 0
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**::

## 2. Signal breakdown

Conservative signals:

* Reliable kernel crash / strong DoS: +1
  The bug can cause recursive kernfs/sysfs locking or a stuck sysfs write path when `array_state=clear` triggers md kobject teardown from the active sysfs writer context.

* Important filesystem/storage path: +1
  The affected code is in the MD RAID/storage control path.

* Requires admin/root/CAP_SYS_ADMIN in typical deployments: -2
  Creating and controlling MD arrays and writing to the relevant `/sys/block/md*/md/array_state` control files normally requires administrative storage-management privileges.

Conservative total: `+1 +1 -2 = 0`

Paranoid adjustment:

* Do not apply full admin penalty in delegated storage-management environments: +2 relative to conservative
  If a reduced-capability storage service, containerized admin tool, or delegated management context can write the MD sysfs control file, the practical privilege level may be closer to PR:L than full host-root.

Paranoid total: `2`

Not counted:

* No generic memory corruption signal.
  The patch shows lifetime/order correction around kobject/sysfs reference release, but the described failure is recursive locking/deadlock, not UAF reclaim, OOB write, arbitrary write, or object confusion.

* No confidentiality or integrity signal.
  There is no supported read primitive, write primitive, credential exposure, fd theft, or security-boundary bypass.

* No remote/network trigger.
  The path is local sysfs MD control, not packet-processing or network-reachable protocol handling.

## 3. Reachability analysis

The bug is triggered by a local actor able to configure or tear down MD arrays through sysfs, especially by writing `clear` to `array_state`. In normal deployments this is root or an administrator with storage-management privileges. Namespace or container delegation could reduce the practical privilege requirement if MD sysfs controls are exposed to a less-trusted management domain, but that is not the default safe assumption. The path is not network reachable and requires an existing or creatable MD device plus access to its sysfs control interface.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like local DoS issue, not an Important-class vulnerability. The realistic impact is a deadlock or stuck teardown path in MD/sysfs handling. Theoretical lifetime ordering concerns exist, but the patch and failure trace support recursive locking rather than exploitable memory corruption. There is no evidence of privilege escalation, sensitive data exposure, or cross-boundary access.

## 5. One-sentence report phrase

A local privileged or delegated storage-management user can trigger a sysfs/kernfs deadlock by clearing an MD array state during teardown, causing a denial of service without evidence of memory corruption or privilege escalation.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED

The issue is local, admin-oriented in typical deployments, DoS-only, and lacks a supported memory-corruption or security-boundary-bypass primitive.

======================================================================
UPSTREAM PATCH SUMMARY
======================================================================

Patch: md: fix array_state=clear sysfs deadlock [ Upstream
Commit: 62c44566da7493ee48ef17e8507bb798338a07cb
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=62c44566da7493ee48ef17e8507bb798338a07cb

Changed files:
  drivers/md/md.c

Diff excerpt:

Not included in this email. See the upstream URL for the full patch.

Full patch:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=62c44566da7493ee48ef17e8507bb798338a07cb

======================================================================
DETAILED REPORT METHODOLOGY
======================================================================

The original Linux kernel CVE announcement for CVE-2026-53125 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-53125

The original CVE announcement normally does not include a security-level
estimate. In particular, it may not contain a CVSS assessment, an impact
level, or enough information to determine whether the reported bug is a
practically relevant security issue. One purpose of this parallel CVE list
is to provide that missing technical and prioritization information.

The original goal of the AL-KERNEL project was to prioritize Linux kernel
CVE analysis automatically before manual review. The system can also help
identify non-security issues that may be suitable for automatic closure.

This report was generated by AL-KERNEL, an AI-assisted Linux kernel
vulnerability analysis system developed by Alexander Larkin.

The first analysis stage combines an autonomous classifier with additional
LLM-based analysis. The autonomous classifier runs locally on a CPU and is
based on a backpropagation neural network. Together, these mechanisms
produce a technical vulnerability description, identify likely weakness
types, estimate CVSS severity, and provide input for ActionableScore.

Two CVSS estimates are retained because incomplete kernel vulnerability
information often permits more than one defensible interpretation:

  Conservative CVSS vector: AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 5.5

The conservative vector represents a lower-impact interpretation.
The Best/paranoid vector intentionally represents a plausible upper-bound
interpretation and should not automatically be treated as demonstrated
real-world impact.

CVSS may also need to be adjusted for a particular Linux deployment,
because actual reachability, privileges, enabled kernel configuration,
hardware, namespaces, exposed device nodes, and other environmental
conditions can differ significantly between systems.

A separate ActionableScore mechanism evaluates practical remediation
urgency. Its analysis may include reachability, attack prerequisites,
subsystem exposure, memory-corruption characteristics, denial-of-service
reliability, and possible confidentiality, integrity, or
privilege-escalation impact.

  Conservative ActionableScore: 0
  Paranoid ActionableScore: 2

The final base severity is taken directly from the second tab-separated
field of the AL-KERNEL classification result. ActionableScore does not
replace or independently override that final AL-KERNEL decision, and
if ActionableScore adjusted impact level of ALKERNEL, then you would see
self-readable flags above like INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN7.

For an AL-KERNEL result of MODERATE, this report uses the following
additional presentation split:

  ActionableScore below 5   -> MODERATE REGULAR
  ActionableScore 5 or more -> MODERATE 7.0

The distinction between MODERATE REGULAR and MODERATE 7.0 makes it
possible to identify Moderate issues that should receive manual analysis
and fixes before lower-priority MODERATE REGULAR issues. In many cases,
MODERATE REGULAR fixes may wait for a later rebase or routine update.

There is one override in which MODERATE REGULAR becomes MODERATE 7.0
even when the ActionableScore is below 5. When the AL-KERNEL result
contains the KPANIC flag, a MODERATE result is always presented as
MODERATE 7.0. The KPANIC flag selected with few regexps without
usage of AI at all, so it helps to detect cases when Kernel Crash happens
and similar (to filter False-Negative results from the LLM usage).

KPANIC indicates that a reliable kernel crash, kernel panic, or similarly
serious kernel availability impact was identified by the classification
workflow.

AL-KERNEL base severity for this report: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

These results are intended to support engineering triage. They are
machine-generated estimates, and cases marked for manual review should
be validated by a human security engineer before final disposition.
For more info read docs linked from here: https://kernelcve.org/
(and you can submit you own patch there to generate such a report
for non-existant CVE-id yet).

Note that in many cases this AI tool selects higher severity, than
real is (means you can expect Importants instead of Moderate 7.0 or
Moderates 7.0 instead of regular Moderates). If you see such cases,
please use reply email interface to add additional manual analyses
info to this particular CVE.
And please, please, let me know when you see Lows instead of Importants
or Important instead of Low (because particular for such cases I
need to tune this AI tool to make it better for this one and next similar).
My contact email for such notifications is alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).