[CVE-2026-72300][MODERATE REGULAR] ASoC: SOF: topology: validate vendor array size before parsing

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

CVE: CVE-2026-72300
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: ASoC: SOF: topology: validate vendor array size before parsing
Commit: 7c6d2d2baeb1e62dc8c6951d27edc16c5ea6e3aa
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7c6d2d2baeb1e62dc8c6951d27edc16c5ea6e3aa
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72300
Analysis date: Sat, 15 Aug 2026 13:27:08 -0400
ActionableScore: 4
ActionableScore lower bound: 2
Actionable bucket: Borderline manual review recommended / Actionable Moderate watchlist
Manual review required: YES

Summary:
A malformed SOF topology blob can cause `sof_parse_token_sets()` to read a vendor array size before a complete header is available, and negative array sizes could bypass the old signedness check, creating a local topology parsing DoS risk with only weak evidence of broader memory corruption.

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

The original Linux kernel CVE announcement for CVE-2026-72300 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72300

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-2026-72300	MODERATE	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:L/I:L/A:H';CWE-125;*CWE-20;CWE-195;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '6.6';DESCR 'A malformed SOF topology blob can make sof_parse_token_sets read the vendor array size before a complete snd_soc_tplg_vendor_array header is available. A truncated trailing vendor array or a negative declared array size can bypass the old validation and drive the parser into an invalid state, causing an out of bounds read and possible kernel crash during audio topology loading. For the CVSS the PR:L is used for the paranoid score because some systems may allow a reduced privilege service account or delegated update path to provide firmware or topology data without full host administration. The issue is not network reachable and normally requires control over local SOF topology or firmware inputs. Impact is at least local denial of service via kernel crash or driver initialization failure. In worst case it may allow limited confidentiality or integrity impact due to malformed kernel parser input and should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline manual review recommended / Actionable Moderate watchlist (with actual score 3)  SKIP CVE-2026-72300 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: 215e5fe75881a7e2425df04aeeed47a903d5cd5d YES  NO NO unknown 	MAYBE	SIMPLEFIX HARDWARE  INCREASED_FROM_LOW_BASED_ON_REQUIREMANUALCHECK DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	-	-	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=4
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 4
* Final recommended bucket: **Borderline manual review recommended / Actionable Moderate watchlist**::

## 2. Signal breakdown

Conservative signals:

* Firmware or topology mediated input: +1. The vulnerable parser consumes SOF topology private data, which is normally supplied through trusted firmware or topology loading paths.
* Weak or indirect corruption candidate: +1. The bug is an OOB read of `array->size` before a full `snd_soc_tplg_vendor_array` header is available, plus a signedness validation bug for negative `asize`.
* Requires admin or trusted update path in typical deployments: -2. Supplying SOF topology data normally requires root, firmware control, package update control, or an equivalent trusted local path.
* Availability impact possible: +1. A malformed topology can plausibly cause driver initialization failure or kernel crash during parsing.
* Constrained primitive: -1. The patch shows validation failure and OOB read prevention, but no OOB write, UAF, attacker-controlled overwrite, callback control, or reclaim primitive.

Paranoid signals:

* Firmware or topology mediated input: +1.
* Weak or indirect corruption candidate: +1.
* Privileged kernel/device parser path: +1. The malformed data is parsed inside a trusted kernel audio driver topology parser.
* Reliable local DoS concern: +1. A truncated or malformed topology can drive invalid parser state and plausibly crash or break SOF audio initialization.
* Reduced privilege or delegated update path concern: +1. Some systems may allow a service account, vendor update mechanism, initramfs pipeline, or image-building process to influence topology files without full interactive host-root control.
* Constrained primitive or no demonstrated attacker-controlled write: -1.

No strong memory corruption bonus is applied. The patch does not show UAF, double free, OOB write, arbitrary write, refcount takeover, type confusion, or page-cache ownership corruption.

## 3. Reachability analysis

The realistic trigger is local control over a malformed SOF topology blob. In typical deployments this is not reachable by an ordinary unprivileged user because topology and firmware files are loaded from protected system locations. Namespace or container access does not normally help unless the container or service can influence host firmware or topology inputs. The path is not network reachable. The issue is relevant mainly on systems using SOF audio topology loading, which is common on some Intel audio platforms but still requires a specific malformed local input path.

Call-site confidence: medium. The changed function and immediate parsing context are visible, but broader topology loading and product-specific update paths are not fully present in the supplied patch.

## 4. Severity interpretation

This behaves more like a borderline Moderate issue than an Important-class vulnerability. The theoretical concern is malformed kernel parser input with an OOB read and signedness validation flaw. The realistic evidence supports local DoS or driver initialization failure, not privilege escalation. A paranoid review is still reasonable because kernel firmware or topology parsers can be security-sensitive when reduced-privilege update paths exist, but the supplied patch does not justify treating it as strong memory corruption or LPE.

## 5. One-sentence report phrase

A malformed SOF topology blob can cause `sof_parse_token_sets()` to read a vendor array size before a complete header is available, and negative array sizes could bypass the old signedness check, creating a local topology parsing DoS risk with only weak evidence of broader memory corruption.

## 6. Manual review recommendation

MANUAL CHECK RECOMMENDED.

Reason: this is a kernel parser bounds and signedness issue in a firmware or topology input path, but the demonstrated primitive is limited and typical triggering requires privileged or trusted topology control.

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

Patch: ASoC: SOF: topology: validate vendor array size before parsing
Commit: 7c6d2d2baeb1e62dc8c6951d27edc16c5ea6e3aa
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=7c6d2d2baeb1e62dc8c6951d27edc16c5ea6e3aa

Commit description:

sof_parse_token_sets() reads array->size while iterating over topology
private data. The loop condition only checks that some data remains, so a
malformed topology with a truncated trailing vendor array can make the
parser read the size field before a full vendor-array header is available.

Validate that the remaining private data contains a complete
snd_soc_tplg_vendor_array header before reading array->size.

The declared array size check also needs to remain signed. asize is an int,
but sizeof(*array) has type size_t, so comparing them directly promotes
negative asize values to unsigned and lets them pass the check,
as reported in the stable review thread reference below.

Cast sizeof(*array) to int when validating the declared array size. This
rejects negative, zero and otherwise too-small sizes before the parser
dispatches to the tuple-specific code.

Link: https://lore.kernel.org/stable/CANiDSCsjR5NHqu_Ui5cOqWdJgFqmYsQ9WR8O7m0WOhngaYXFpw@mail.gmail.com/t/#m9b3be379221e79327cc13fd71009287368ef4f23
Fixes: 215e5fe ("ASoC: SOF: topology: reject invalid vendor array size in token parser")
Cc: stable@vger.kernel.org
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Link: https://patch.msgid.link/20260603-sof-topology-array-size-signed-v1-1-84f97879a4ef@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Changed files:
  sound/soc/sof/topology.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=7c6d2d2baeb1e62dc8c6951d27edc16c5ea6e3aa

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

The original Linux kernel CVE announcement for CVE-2026-72300 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-72300

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:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS score: 6.6

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: 2
  Paranoid ActionableScore: 4

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).