[CVE-2026-72302][MODERATE 7.0] ASoC: SOF: ipc3-control: Use overflow checks in control_update size calc

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

CVE: CVE-2026-72302
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: ASoC: SOF: ipc3-control: Use overflow checks in control_update size calc
Commit: 6856b3c23b0995eefad5a6142b4365ef70e1fe4a
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6856b3c23b0995eefad5a6142b4365ef70e1fe4a
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72302
Analysis date: Sun, 16 Aug 2026 01:32:38 -0400
ActionableScore: 6
ActionableScore lower bound: 4
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum**:: Actionable Moderate at minimum. Strong Important only if low-privilege control over the malformed SOF IPC control data is confirmed.
Manual review required: YES

Summary:
An integer overflow in ASoC SOF IPC3 control update size calculation can allow firmware-provided `num_elems` to bypass validation on 32-bit platforms and may lead to out-of-bounds access in kernel audio control handling.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-72302 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72302

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 7.0
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-2026-72302	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H';CWE-190;CWE-131;CWE-119;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7';DESCR 'An integer overflow in the ASoC SOF IPC3 control update path can occur because the expected size is calculated from firmware provided cdata num_elems. On 32-bit platforms the calculation can wrap to a small value, allowing the size validation to pass with inconsistent control data and potentially causing out-of-bounds access in snd_sof_update_control. For the CVSS the PR:L is used in the paranoid score because a local user or local service with access to audio control paths may be able to influence the firmware control update flow without full administrator privileges, although the more typical reliable trigger requires firmware or topology control. The issue is not network reachable. Impact is at least local denial of service via kernel crash and in worst case may allow confidentiality or integrity impact due to memory corruption, so it should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 5)	YES	OOB SIMPLEFIX HARDWARE  DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=6
ActionableScoreLower=4

## 1. ActionableScore

* Conservative score: 4
* Paranoid score: 6
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**:: Actionable Moderate at minimum. Strong Important only if low-privilege control over the malformed SOF IPC control data is confirmed.

## 2. Signal breakdown

Conservative signals:

* Firmware-mediated external influence: +1. The malformed `cdata->num_elems` is firmware-provided.
* Memory corruption, weak/indirect corruption candidate: +1. Integer overflow can bypass size validation and lead to out-of-bounds access, but no arbitrary write or controlled reclaim primitive is shown.
* Privileged kernel/device-management memory corruption path: +1. The bug is in SOF audio firmware IPC handling inside a trusted kernel driver path.
* Availability impact realistic: +1. Out-of-bounds access in kernel context can plausibly cause a kernel crash.

Paranoid additional signals:

* Local low-privilege trigger concern: +1. A local user or audio service may be able to trigger the affected control update path, although direct control over `num_elems` is not proven.
* Weak LPE concern: +1. The primitive is an overflow-driven validation bypass into OOB access, which is a memory-corruption candidate, but not a demonstrated LPE primitive.
* Confidentiality impact plausible: +1. OOB read-style behavior is possible depending on `snd_sof_update_control()` access pattern.
* Integrity impact plausible: +1. OOB write or corruption cannot be excluded from the patch context.
* Hard or special conditions: -1. The issue is specifically described for 32-bit platforms and depends on malformed firmware-provided IPC data.
* Constrained or unproven primitive: -1. No attacker-controlled overwrite target, reclaim primitive, or exploit chain is demonstrated.

Call-site confidence: medium. The patch identifies the downstream function `snd_sof_update_control()`, but the full caller and data-flow context is not included.

## 3. Reachability analysis

The most reliable trigger appears to require malformed SOF firmware IPC data or control over firmware/topology behavior, which is usually privileged or firmware-mediated. It is not network reachable. A lower-privilege local trigger is plausible only if an unprivileged user or local audio service can cause the firmware to return attacker-influenced control data, but this is not proven by the patch alone. The issue is also constrained to 32-bit arithmetic behavior, reducing broad default exposure.

Namespaces and containers likely do not materially reduce the requirement unless audio device access is delegated into the container. If `/dev/snd/*` or relevant ALSA controls are exposed to a container or sandboxed service, practical reachability may increase.

## 4. Severity interpretation

This is not an ordinary low-risk validation cleanup because the commit explicitly identifies integer overflow leading to possible out-of-bounds access. Conservative handling is Borderline or manual-review Moderate because the trigger is firmware-mediated and the primitive is not fully characterized. Paranoid handling reaches Actionable Moderate because memory corruption in a privileged device driver path may have confidentiality, integrity, and availability implications if the malformed control data can be influenced from a lower-privilege context.

This should not be treated as confirmed Important without more evidence of controlled OOB write, reclaim, type confusion, or practical low-privilege triggering.

## 5. One-sentence report phrase

An integer overflow in ASoC SOF IPC3 control update size calculation can allow firmware-provided `num_elems` to bypass validation on 32-bit platforms and may lead to out-of-bounds access in kernel audio control handling.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: this is a firmware-fed integer-overflow-to-OOB-access candidate in a privileged kernel driver path. The exact impact depends on whether the downstream access is read-only, write-capable, crash-only, or attacker-influenceable from local audio interfaces.

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

Patch: ASoC: SOF: ipc3-control: Use overflow checks in control_update size calc
Commit: 6856b3c23b0995eefad5a6142b4365ef70e1fe4a
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=6856b3c23b0995eefad5a6142b4365ef70e1fe4a

Commit description:

In sof_ipc3_control_update(), the expected_size calculation uses
firmware-provided cdata->num_elems in arithmetic that could overflow
on 32-bit platforms, wrapping to a small value. This would allow the
cdata->rhdr.hdr.size comparison to pass with mismatched sizes,
potentially leading to out-of-bounds access in snd_sof_update_control.

Use check_mul_overflow() and check_add_overflow() to detect and reject
overflowed size calculations.

Fixes: 10f461d ("ASoC: SOF: Add IPC3 topology control ops")
Cc: stable@vger.kernel.org
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@linux.intel.com>
Reviewed-by: Liam Girdwood <liam.r.girdwood@intel.com>
Reviewed-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://patch.msgid.link/20260609083458.31193-4-peter.ujfalusi@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  sound/soc/sof/ipc3-control.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=6856b3c23b0995eefad5a6142b4365ef70e1fe4a

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

The original Linux kernel CVE announcement for CVE-2026-72302 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72302

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:L/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 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: 4
  Paranoid ActionableScore: 6

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 7.0

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).