[CVE-2026-72480][MODERATE REGULAR] iio: adc: xilinx-ams: fix out-of-bounds channel lookup in event handling [ Upstream

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

CVE: CVE-2026-72480
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: iio: adc: xilinx-ams: fix out-of-bounds channel lookup in event handling [ Upstream
Commit: 116d1f8805ae2daadbac89d24da4c0da50b9edae
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=116d1f8805ae2daadbac89d24da4c0da50b9edae
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72480
Analysis date: Sun, 16 Aug 2026 08:20:45 -0400
ActionableScore: 3
ActionableScore lower bound: 1
Actionable bucket: Borderline Moderate. Manual review recommended
Manual review required: YES

Summary:
A Xilinx AMS IIO event can map to a non existent channel and cause `ams_handle_event()` to dereference a one past end channel pointer, leading to invalid kernel memory access and possible DoS on systems using the affected driver.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-72480 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72480

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
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CVE-2026-72480	MODERATE	CHECK WITH IMPACT FROM ORIG NN IMPORTANT	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-823;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.3';DESCR 'The Xilinx AMS IIO event handler can use an out of bounds channel pointer because ams_event_to_channel returns a pointer one element past dev channels when no matching scan_index is found. ams_handle_event then dereferences that pointer while processing a hardware event, which can cause invalid kernel memory access and a kernel crash. For the CVSS the PR:L is used in the paranoid score because reliable triggering would require a local user or process that can influence IIO event configuration or otherwise cause the device event path to run, but it does not require full kernel privileges in the conservative review model. The issue is not network reachable and is specific to systems using the xilinx-ams ADC driver. Impact is at least local denial of service via kernel crash, with limited confidentiality impact in the paranoid score due to an out of bounds read in a kernel event path.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline Moderate. Manual review recommended (with actual score 2)  SKIP CVE-2026-72480 UNKNOWN SKIP No affected files built, so skip this CVE NO  - - unknown 	MAYBE	WRITE OOB SIMPLEFIX IMPROVEONLY  DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=3
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 3
* Final recommended bucket: **Borderline Moderate. Manual review recommended**

## 2. Signal breakdown

Conservative signals:

* Memory corruption, weak/indirect corruption candidate: +1
  `ams_event_to_channel()` can return `&dev->channels[dev->num_channels]`, a one-past-end pointer, and the caller dereferences it. This is an OOB read / invalid object pointer, not an OOB write or UAF.
* Reliable kernel crash / strong DoS: +1
  The commit states this can lead to invalid memory access in `ams_handle_event()`, plausibly causing an Oops or crash.
* Physical-only or rare hardware-only condition: -1
  The issue is limited to systems using the Xilinx AMS ADC driver and depends on the device event path. I apply only -1 rather than -2 because the affected code is a normal in-kernel event handler once the hardware is present.

Paranoid additional signals:

* Firmware-mediated or hardware-mediated external influence: +1
  The invalid event value appears to come through hardware event handling. If the monitored analog or alarm source can be influenced externally, the trigger may not be purely local software.
* Confidentiality impact plausible: +1
  The primitive is read-only OOB access to adjacent kernel memory interpreted as an `iio_chan_spec`. There is no direct disclosure primitive shown, but limited C impact is defensible for manual triage.

Not awarded:

* No strong LPE plausibility. There is no UAF reclaim, controlled overwrite, callback control, type confusion, or arbitrary write.
* No generic strong memory corruption. The patch shows an OOB read / invalid pointer dereference only.
* No remote/network reachability. This is not a network path.
* No Dirty-Pipe-like or page-cache/shared-page primitive.

## 3. Reachability analysis

The bug is reachable through the Xilinx AMS IIO event handling path when an event maps to a `scan_index` that has no matching channel entry. Reliable triggering likely depends on hardware state, event configuration, or the ability to cause device events. A local user may be able to interact with IIO interfaces depending on device permissions, but full unprivileged reachability is not proven from the patch alone.

Namespaces and containers do not materially broaden exposure unless the device node or relevant sysfs controls are delegated into the container. The path is not default-exposed on generic systems because it requires Xilinx AMS hardware and the corresponding driver.

Call-site confidence: high. The patch includes both the faulty helper and the immediate dereferencing caller.

## 4. Severity interpretation

This behaves like a borderline Moderate kernel OOB-read / crash issue rather than an Important vulnerability. The theoretical concern is limited kernel memory being read past the channel array and interpreted as a channel structure. Realistic evidence supports invalid memory access and DoS, but not privilege escalation or attacker-controlled memory corruption.

The paranoid score keeps this in manual-review territory because kernel OOB reads in event paths can be underestimated, especially when hardware input affects indexing. It should not be auto-promoted to Important without evidence of disclosure, write capability, UAF, or controllable object confusion.

## 5. One-sentence report phrase

A Xilinx AMS IIO event can map to a non existent channel and cause `ams_handle_event()` to dereference a one past end channel pointer, leading to invalid kernel memory access and possible DoS on systems using the affected driver.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Manual review is recommended because this is an OOB read / invalid pointer dereference in a kernel event path, but the patch does not show a strong exploitation primitive beyond crash or limited adjacent memory interpretation.

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

Patch: iio: adc: xilinx-ams: fix out-of-bounds channel lookup in event handling [ Upstream
Commit: 116d1f8805ae2daadbac89d24da4c0da50b9edae
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=116d1f8805ae2daadbac89d24da4c0da50b9edae

Changed files:
  drivers/iio/adc/xilinx-ams.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=116d1f8805ae2daadbac89d24da4c0da50b9edae

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

The original Linux kernel CVE announcement for CVE-2026-72480 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72480

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