[CVE-2026-46327][LOW] dm: fix unlocked test for dm_suspended_md [ Upstream

[AL-KERNEL <alkernel@kernelcve.org>]

CVE: CVE-2026-46327
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: dm: fix unlocked test for dm_suspended_md [ Upstream
Commit: 175ac0a6115400278d3900f5a04a58b17b3f6cd0
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=175ac0a6115400278d3900f5a04a58b17b3f6cd0
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46327
Analysis date: Tue, 09 Jun 2026 09:36:11 -0400
ActionableScore: 2
ActionableScore lower bound: 1
Actionable bucket: Ordinary Moderate / Low-like
Manual review required: NO

Summary:
A local race in `dm_blk_report_zones()` could allow zone reporting to proceed across a concurrent device suspension window, causing inconsistent block-device behavior or a device-level denial of service, with no evidence of memory corruption or privilege escalation.

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

The original Linux kernel CVE announcement for CVE-2026-46327 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46327

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-2026-46327	LOW	CHECK	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';CWE-362;CWE-367;CWE-667;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '4.7';DESCR 'dm_blk_report_zones() checked dm_suspended_md() before taking a live table reference, leaving a TOCTOU window where the device could be suspended immediately after the test. A local caller that can issue zone report operations could then run the report path against a device that is entering the suspended state, which can cause failed or inconsistent block device operations and a denial of service at the affected dm device level. For the CVSS the PR:L is used in the paranoid case because a local user or service may have access to the block device while suspend or reload is driven by management tooling. The issue is not network reachable and there is no evidence of a memory corruption primitive or privilege escalation. Impact is availability only.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate / Low-like (with actual score 2)	YES	DISK SIMPLEFIX HARDWARE LINUS 	YES	NO	checked

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

ActionableScore=2
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate / Low-like**

## 2. Signal breakdown

Conservative signals:

* Important filesystem/storage path: +1. The affected code is in device mapper zoned block reporting, so it is part of a storage control path.
* Hard or unreliable race / special timing required: -1. The issue depends on suspension happening after the unlocked `dm_suspended_md()` test and before safe table handling.
* Requires admin/root/CAP_SYS_ADMIN in typical deployments: -2. Reliable control of device mapper suspend/reload normally requires administrative privileges.
* Availability impact realistic: +1. The likely impact is failed or inconsistent zone report behavior, possibly a local device-level DoS.

Conservative subtotal is effectively 1 after keeping the score non-negative and recognizing limited availability impact.

Paranoid signals:

* Local trigger condition: +1. A local process with access to the relevant block device may issue zone report operations while management tooling suspends or reloads the dm device.
* Important filesystem/storage path: +1. Device mapper and zoned block reporting are storage infrastructure paths.
* Availability impact realistic: +1. The race can cause incorrect behavior during suspend and zone reporting.
* Hard race / timing required: -1. Triggering requires a narrow suspend/report interleaving.

Paranoid total: 2.

No memory corruption, UAF, OOB write, refcount takeover, page-cache corruption, privilege escalation, confidentiality impact, or integrity impact is supported by this patch.

## 3. Reachability analysis

The bug is locally reachable through the block device zone reporting path. In typical deployments, an attacker would need access to the affected dm block device, while device suspension or reload is normally performed by privileged management code. Namespaces or containers may lower practical exposure only if the block device is delegated into the container or a service account can issue relevant ioctls, but that still does not provide evidence of memory corruption or privilege escalation. The path is not network reachable.

## 4. Severity interpretation

This behaves like an ordinary Moderate or Low-like storage race, not an Important-class issue. The patch fixes a TOCTOU ordering problem around `dm_suspended_md()` and `dm_get_live_table()`, but it does not show stale table use after free, attacker-controlled reuse, arbitrary write, or sensitive data exposure. The realistic impact is availability only, mainly failed or inconsistent block-device operations during suspend.

## 5. One-sentence report phrase

A local race in `dm_blk_report_zones()` could allow zone reporting to proceed across a concurrent device suspension window, causing inconsistent block-device behavior or a device-level denial of service, with no evidence of memory corruption or privilege escalation.

## 6. Manual review recommendation

NO MANUAL CHECK NEEDED.

This can be handled as a low-priority local storage race because the patch shows availability-only behavior, requires special timing, is not remotely reachable, and does not expose a concrete memory corruption or security-boundary bypass primitive.

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

Patch: dm: fix unlocked test for dm_suspended_md [ Upstream
Commit: 175ac0a6115400278d3900f5a04a58b17b3f6cd0
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=175ac0a6115400278d3900f5a04a58b17b3f6cd0

Changed files:
  drivers/md/dm-zone.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=175ac0a6115400278d3900f5a04a58b17b3f6cd0

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

The original Linux kernel CVE announcement for CVE-2026-46327 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46327

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:H/PR:H/UI:N/S:U/C:N/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.7

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: 1
  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).