[CVE-2026-46190][MODERATE REGULAR] mtd: spi-nor: debugfs: fix out-of-bounds read in spi_nor_params_show()

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

CVE: CVE-2026-46190
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: mtd: spi-nor: debugfs: fix out-of-bounds read in spi_nor_params_show()
Commit: 9a80c458320e0514e11945402dd6e48fcee05524
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9a80c458320e0514e11945402dd6e48fcee05524
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46190
Analysis date: Thu, 28 May 2026 10:08:25 -0400
ActionableScore: 3
ActionableScore lower bound: 1
Actionable bucket: Borderline, manual review recommended
Manual review required: YES

Summary:
`spi_nor_params_show()` used `sizeof()` instead of `ARRAY_SIZE()` for a flag-name pointer array, allowing a privileged local debugfs reader to trigger an out-of-bounds read and possible kernel information disclosure or crash.

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

The original Linux kernel CVE announcement for CVE-2026-46190 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46190

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: MODERATE REGULAR
Manual review required: YES

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

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

CVE-2026-46190	MODERATE	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:L/I:N/A:H';CWE-125;CWE-129;CWE-467;*CWE-200;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:L';BEST CVSS score: '5.3';DESCR 'spi nor debugfs used sizeof(snor_f_names) as the number of flag name entries, but sizeof returns the byte size of the pointer array. If a flag bit beyond the real array length is set, spi_nor_print_flags can read past the names array and treat adjacent memory as a string pointer. For the CVSS the PR:L is used for the paranoid score only when debugfs access is delegated to a reduced privilege user or container. The base case is closer to PR:H because reading this debugfs file normally requires privileged local access. The issue is not network reachable. Impact is limited to possible kernel information disclosure or crash from an out-of-bounds read, with no supported write primitive or privilege escalation path.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review recommended (with actual score 2) 	MAYBE	OOB SIMPLEFIX DEBUGFS LINUS  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH	-	-	checked

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

ActionableScore=3
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 3
* Final recommended bucket: **Borderline, manual review recommended**::

## 2. Signal breakdown

Conservative signals:

* Confidentiality impact plausible: +1. `spi_nor_print_flags()` can read past the `snor_f_names` pointer array and may treat adjacent memory as a string pointer.
* Availability impact possible: +1. If the out-of-bounds pointer is invalid, reading the debugfs file may trigger a kernel fault.
* Requires privileged debugfs access in typical deployments: -2. SPI NOR debugfs files are normally readable only by root or privileged local users.

Paranoid additional signal:

* Local delegated access: +1. Some test, embedded, or containerized environments may expose debugfs or selected debugfs entries to reduced-privilege users.

Not counted:

* No write primitive.
* No UAF, double free, heap overwrite, or arbitrary pointer write.
* No network reachability.
* No privilege escalation evidence.
* The OOB read is limited to a debugfs show path and depends on `nor->flags` containing a bit beyond the real names array length.

## 3. Reachability analysis

The trigger is local: reading the SPI NOR debugfs parameter file causes `spi_nor_params_show()` to print flags. Practical exploitation requires debugfs to be mounted and the relevant file to be readable by the attacker.

In normal production systems, debugfs is restricted to privileged users, so the conservative impact is low. In embedded, lab, or container environments where debugfs is exposed to less privileged users, the issue becomes more relevant. The affected flags usually come from device or driver state, so attacker control over the exact OOB index may be limited.

## 4. Severity interpretation

This behaves like a low-to-borderline Moderate information disclosure or crash issue. It is not an Important-class memory corruption bug.

The theoretical concern is kernel pointer/string disclosure or a crash from reading an invalid pointer. The realistic impact is limited by debugfs permissions and by the lack of a write or lifetime-corruption primitive.

## 5. One-sentence report phrase

`spi_nor_params_show()` used `sizeof()` instead of `ARRAY_SIZE()` for a flag-name pointer array, allowing a privileged local debugfs reader to trigger an out-of-bounds read and possible kernel information disclosure or crash.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Review debugfs exposure and whether untrusted users can read the affected SPI NOR debugfs file. If debugfs is root-only, this can likely be treated as low priority.

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

Patch: mtd: spi-nor: debugfs: fix out-of-bounds read in spi_nor_params_show()
Commit: 9a80c458320e0514e11945402dd6e48fcee05524
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9a80c458320e0514e11945402dd6e48fcee05524

Commit description:

Sashiko noticed an out-of-bounds read [1].

In spi_nor_params_show(), the snor_f_names array is passed to
spi_nor_print_flags() using sizeof(snor_f_names).

Since snor_f_names is an array of pointers, sizeof() returns the total
number of bytes occupied by the pointers
	(element_count * sizeof(void *))
rather than the element count itself. On 64-bit systems, this makes the
passed length 8x larger than intended.

Inside spi_nor_print_flags(), the 'names_len' argument is used to
bounds-check the 'names' array access. An out-of-bounds read occurs
if a flag bit is set that exceeds the array's actual element count
but is within the inflated byte-size count.

Correct this by using ARRAY_SIZE() to pass the actual number of
string pointers in the array.

Cc: stable@vger.kernel.org
Fixes: 0257be7 ("mtd: spi-nor: expose internal parameters via debugfs")
Closes: https://sashiko.dev/#/patchset/20260417-die-erase-fix-v2-1-73bb7004ebad%40infineon.com [1]
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Reviewed-by: Takahiro Kuwano <takahiro.kuwano@infineon.com>
Reviewed-by: Michael Walle <mwalle@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  drivers/mtd/spi-nor/debugfs.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=9a80c458320e0514e11945402dd6e48fcee05524

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

The original Linux kernel CVE announcement for CVE-2026-46190 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-46190

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:L/I:N/A:L
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:H
  The Best / paranoid CVSS score: 5.3

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: 3

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: MODERATE
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): MODERATE REGULAR

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).