[CVE-2026-89577][LOW] dm-io: report non-retryable errors separatedly

[CVE-2026-89577][LOW] dm-io: report non-retryable errors separatedly

[AL-KERNEL]

CVE: CVE-2026-89577
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: dm-io: report non-retryable errors separatedly
Commit: 49694a363f7ecd5a52d1ea1a13c287ad6d196c35
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=49694a363f7ecd5a52d1ea1a13c287ad6d196c35
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89577
Analysis date: Fri, 11 Sep 2026 23:47:12 -0400
ActionableScore: 2
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-89577 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89577

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-2026-89577	LOW	https://www.kernelcve.org/list/?q=CVE-2026-89577 CHECK WITH IMPACT FROM ORIG NN LOW	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-754;CWE-703;CWE-391;Other CVSS 'AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.5';DESCR 'dm-io did not distinguish unsupported or invalid block status values from real IO failures when reporting completion bitmaps to upper device mapper users. In dm-raid1 this could make BLK_STS_NOTSUPP or BLK_STS_INVAL look like a mirror leg failure when unaligned bio vectors are used, causing an incorrect degraded state and reduced storage availability. For the CVSS the PR:L value is used because triggering requires a local user or process that can issue IO through the affected dm-raid1 stack, rather than a remote unauthenticated network path. The issue is not network reachable and does not provide a memory corruption primitive. Impact is primarily denial of service through incorrect mirror leg failure handling and possible storage degradation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2)  SKIP CVE-2026-89577 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: url YES  NO NO unknown 	MAYBE	DISK INIT WARNONLY LINUS  INCREASED_FROM_LOW_BASED_ON_HIGHCVSSSCORE DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_ACTIONABLESCORELESSTHAN3	-	-	checked

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

ActionableScore=2
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: 2
* Conservative score: 2
* Raw paranoid score: 2
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate**::

No floor or cap was applied.

2. Signal breakdown

Positive signals:

* +1 Local below-host-admin trigger. The commit states that misbehavior occurs when the user uses unaligned bio vectors on dm-raid1, so a local process with access to the affected storage path can plausibly trigger the condition without host-admin-equivalent privilege.
* +1 Availability impact realistic. dm-raid1 may incorrectly fail a mirror leg after BLK_STS_NOTSUPP or BLK_STS_INVAL is reported as a normal I/O error, reducing storage availability or redundancy.

Non-awarded signals:

* Real UAF not awarded. The patch does not show stale object use, double free, refcount misuse, or post-lifetime access.
* Memory corruption not awarded. The bug is error classification and propagation, not OOB access, arbitrary write, UAF, or type confusion.
* Confidentiality and integrity not awarded. The patch does not establish protected data disclosure or unauthorized modification of another principal's data.
* Reliable kernel crash not awarded. The demonstrated consequence is incorrect mirror leg failure or degraded dm-raid1 behavior, not a kernel panic.
* Strong DoS extra point not awarded. Storage degradation is already counted as the availability consequence.
* Manual review preservation signals not awarded. There is no concrete corruption, ownership/COW violation, authorization bypass, or unresolved lifetime primitive.

3. Reachability analysis

The affected path is local storage I/O through a dm-raid1 configuration. A prior administrator must have configured dm-raid1, but the vulnerable behavior itself can plausibly be reached by a local user or process that can issue I/O producing unaligned bio vectors on the affected volume. This is not network reachable. No namespace-scoped privilege chain is involved. No special hardware requirement is established beyond using the relevant device mapper RAID1 stack. This is not a race and no timing penalty applies.

4. Primitive and severity interpretation

The primitive is a logic and error-handling bug in dm-io completion reporting. BLK_STS_NOTSUPP and BLK_STS_INVAL were reported together with ordinary I/O errors through error_bits, causing dm-raid1 to treat unsupported or invalid request status as a real mirror leg failure. This is PrimitiveClass NONE because no kernel memory corruption, lifetime violation, repeated release/refcount mutation, security-boundary bypass, or controlled corruption primitive is established. The demonstrated consequence is reduced storage availability through incorrect mirror degradation. Speculative privilege escalation is not supported.

ImportantCandidate=NO because the issue is a DoS/storage-availability logic bug without corruption or boundary bypass. AutoDowngradeAllowed=YES because there is no unresolved Important-grade primitive that would be lost by ordinary Moderate handling.

5. One-sentence report phrase

dm-io incorrectly mixed unsupported or invalid block status with real I/O errors, allowing local I/O with unaligned bio vectors on dm-raid1 to wrongly fail a mirror leg and reduce storage availability.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: this is a local logic/error-classification issue with availability impact only, and the patch does not establish memory corruption, UAF, authorization bypass, or privilege escalation.

7. Call-site confidence

Call-site confidence: medium

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

Patch: dm-io: report non-retryable errors separatedly
Commit: 49694a363f7ecd5a52d1ea1a13c287ad6d196c35
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=49694a363f7ecd5a52d1ea1a13c287ad6d196c35

Commit description:

The error codes BLK_STS_NOTSUPP and BLK_STS_INVAL should not cause leg
failure on dm-raid1. This patch changes the interface to dm-io, so that
it reports two error bitmaps - error_bits and unsup_bits. The unsup_bit
bitmap tracks BLK_STS_NOTSUPP or BLK_STS_INVAL errors, the error_bits
bitmap tracks all the other errors.

dm-raid1 is changed so that it won't fail a leg if it receives an error
in the unsup_bits bitmap.

This patch (with 62dc37a ) fixes misbehavior if the user uses
unaligned bio vectors on dm-raid1.

Fixes: 7eac331 ("iomap: simplify direct io validity check")
Fixes: 5ff3f74 ("block: simplify direct io validity check")
Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/md/dm-bufio.c
  drivers/md/dm-integrity.c
  drivers/md/dm-io.c
  drivers/md/dm-kcopyd.c
  drivers/md/dm-log.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=49694a363f7ecd5a52d1ea1a13c287ad6d196c35

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

The original Linux kernel CVE announcement for CVE-2026-89577 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-89577

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:L/UI:N/S:U/C:N/I:N/A:L
  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: unknown
  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).