[CVE-2026-72261][MODERATE 7.0] ASoC: SOF: ipc3-control: Validate size in snd_sof_update_control

[CVE-2026-72261][MODERATE 7.0] ASoC: SOF: ipc3-control: Validate size in snd_sof_update_control

[AL-KERNEL]

CVE: CVE-2026-72261
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: YES
Patch: ASoC: SOF: ipc3-control: Validate size in snd_sof_update_control
Commit: 1dc25a3e06364f48c4ef06016852f8b82425151a
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1dc25a3e06364f48c4ef06016852f8b82425151a
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72261
Analysis date: Sat, 15 Aug 2026 20:12:54 -0400
ActionableScore: 7
ActionableScore lower bound: 5
Actionable bucket: Strong Important candidate / Actionable Moderate at minimum
Manual review required: YES

Summary:
An out-of-bounds write in the ASoC SOF IPC3 control update path can occur when firmware-provided control data is copied using `cdata->num_elems` without validating it against the actual allocation size, making this a firmware-mediated local kernel memory corruption issue with DoS and possible privilege-escalation impact.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-72261 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72261

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-2026-72261	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-787;CWE-120;*CWE-20;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H';BEST CVSS score: '7';DESCR 'An out-of-bounds write in the ASoC SOF IPC3 control update path can occur because snd_sof_update_control() validates firmware-provided cdata num_elems against local control metadata but not against the real ipc_control_data allocation size. If the stored data size is inconsistent with the allocated buffer, memcpy can write past the end of local_cdata data and corrupt kernel heap memory. For the CVSS the PR:L paranoid interpretation is used because a local user or service that can reach the SOF control path may be able to trigger firmware control updates in some deployments, although reliable control of the malformed IPC payload or inconsistent state is environment dependent. The issue is not network reachable and depends on local audio driver and SOF firmware or topology behavior. Impact is at least local denial of service via kernel crash and in worst case may allow confidentiality and integrity impact or privilege escalation due to kernel memory corruption.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Strong Important candidate / Actionable Moderate at minimum (with actual score 7)	YES	OOB SIMPLEFIX ERRORPATH HARDWARE KPANIC  KPANIC INCREASED_TO_HIGH_BASED_ON_ACTIONABLESCOREHIGHEREQTHAN6 DECREASED_TO_MODERATE7_BASED_ON_FALSEPOSCHECKOFKP	NO	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=7
ActionableScoreLower=5

## 1. ActionableScore

* Conservative score: 5
* Paranoid score: 7
* Final recommended bucket: **Strong Important candidate / Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Firmware-mediated external influence: +1. The oversized `cdata->num_elems` and copied payload are firmware-provided.
* Memory corruption, strong corruption primitive: +2. The bug is a kernel heap out-of-bounds write via `memcpy()` past the allocated `ipc_control_data` buffer.
* Weak LPE concern: +1. Kernel heap OOB write can sometimes be shaped into privilege escalation, but the patch does not show controlled target selection, reclaim, callback control, or arbitrary write.
* Privileged kernel/device-management memory corruption path: +1. The corruption occurs in a trusted ASoC SOF firmware/control path.
* Reliable kernel crash / strong DoS: +1. Writing past a kernel allocation can realistically crash the kernel.
* Confidentiality impact plausible: +1. Plausible only as a secondary effect of kernel heap corruption.
* Integrity impact plausible: +1. Plausible because the primitive is an OOB write.
* Requires admin/root/firmware/topology control in typical deployments: -2. Reliable triggering likely requires malicious or compromised firmware, invalid topology/control state, or privileged control over the SOF stack.
* Hard or unreliable conditions: -1. The bug requires `local_cdata->data->size` to become inconsistent with the real allocation and then receive an oversized firmware update.

Paranoid delta:

* Local unprivileged trigger: +1. In some deployments, local users or services may reach ALSA/SOF controls and indirectly cause firmware control updates.
* Privilege escalation plausible is kept at weak +1, not strong +2, because no concrete reclaim, object replacement, or arbitrary write primitive is shown.
* The admin/root penalty is not applied in the paranoid interpretation because reduced-capability services or local audio-control access may lower practical reachability.

## 3. Reachability analysis

The affected path is local and firmware-mediated, not network reachable. The most realistic trigger requires a SOF-enabled audio device and a malformed or inconsistent firmware/control-data state. Typical reliable exploitation likely requires privileged influence over firmware, topology loading, or driver control state. A weaker but relevant paranoid interpretation is that a local user or service with access to ALSA/SOF control paths may be able to trigger the vulnerable update path indirectly, depending on product policy and device configuration.

Namespaces and containers do not obviously make this broadly reachable unless the audio device or relevant control interfaces are delegated into the container. The path is common on some Intel audio platforms but not a generic server exposure.

Call-site confidence: medium-high. The direct vulnerable sink is visible as `memcpy(local_cdata->data, cdata->data, cdata->num_elems)`, but the full set of ways to corrupt or influence `local_cdata->data->size` is not shown in the supplied patch.

## 4. Severity interpretation

This is more than an ordinary Moderate because it is a real kernel heap OOB write, not just a validation warning or DoS-only bug. Realistic exploitability is constrained by firmware and control-path reachability, so the conservative score remains Actionable Moderate rather than automatically Important. The paranoid score reaches Strong Important candidate because kernel heap corruption with a firmware-provided size and payload deserves manual review even without a demonstrated LPE exploit.

Theoretical impact includes kernel crash and possible privilege escalation. Realistic evidence supports at least local DoS and potential memory corruption, but does not demonstrate arbitrary code execution or a reliable LPE chain.

## 5. One-sentence report phrase

An out-of-bounds write in the ASoC SOF IPC3 control update path can occur when firmware-provided control data is copied using `cdata->num_elems` without validating it against the actual allocation size, making this a firmware-mediated local kernel memory corruption issue with DoS and possible privilege-escalation impact.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

This is a kernel heap OOB write in a trusted driver/firmware control path. Even though reachability is constrained, the primitive is serious enough that it should not be auto-closed without checking local control-path exposure, firmware trust assumptions, topology loading policy, and whether unprivileged users can trigger relevant SOF control updates.

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

Patch: ASoC: SOF: ipc3-control: Validate size in snd_sof_update_control
Commit: 1dc25a3e06364f48c4ef06016852f8b82425151a
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=1dc25a3e06364f48c4ef06016852f8b82425151a

Commit description:

In snd_sof_update_control(), firmware-provided cdata->num_elems is
checked against local_cdata->data->size but never against the actual
allocation size. If local_cdata->data->size was previously set to an
inconsistent value, the memcpy could write past the allocated buffer.

Add a bounds check to ensure num_elems fits within the available space
in the ipc_control_data allocation before copying.

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/20260609083458.31193-5-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=1dc25a3e06364f48c4ef06016852f8b82425151a

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

The original Linux kernel CVE announcement for CVE-2026-72261 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72261

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:H/I:H/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: 5
  Paranoid ActionableScore: 7

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: YES
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).