* [CVE-2026-97445][MODERATE REGULAR] ACPICA: Enhance buffer validation in acpi_ut_walk_aml_resources() [ Upstream
@ 2026-09-24 22:40 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-24 22:40 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-97445
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: ACPICA: Enhance buffer validation in acpi_ut_walk_aml_resources() [ Upstream
Commit: f65e2ef7ccca11dc874f48aff996a6a26528f8e7
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f65e2ef7ccca11dc874f48aff996a6a26528f8e7
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97445
Analysis date: Thu, 24 Sep 2026 18:40:36 -0400
ActionableScore: 2
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO
Summary:
No one-sentence report phrase was found.
======================================================================
ABOUT THIS REPORT
======================================================================
The original Linux kernel CVE announcement for CVE-2026-97445 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97445
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: NO
A detailed explanation of the methodology and priority rules is included
at the end of this message.
======================================================================
AL-KERNEL CLASSIFICATION RESULT
======================================================================
CVE-2026-97445 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-97445 CHECK WITH IMPACT FROM ORIG NN MODERATE 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-20;CWE-119;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.3';DESCR 'An out of bounds read can occur in ACPICA acpi_ut_walk_aml_resources when malformed AML resource descriptors are processed without confirming that the remaining buffer is large enough for all accessed fields. A short large resource descriptor can cause access to the serial bus type field beyond the supplied AML buffer. This may cause a kernel fault or crash when the kernel evaluates attacker controlled ACPI resource data. For the CVSS the PR:L paranoid score assumes a local actor can trigger evaluation of controlled or dynamically supplied ACPI resources in an environment with delegated ACPI related capabilities. The normal deployment case more commonly requires firmware control or administrative table loading. The issue is not directly network reachable. Impact is primarily denial of service. Limited confidentiality impact is retained only for the paranoid score because the defect is an out of bounds read. No integrity impact or privilege escalation primitive is demonstrated by the patch.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 2) YES OOB DANGER DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=2
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 2
* Conservative score: 2
* Raw paranoid score: 2
* Paranoid score: 2
* Final recommended bucket: **Ordinary Moderate**::
No floor or cap was applied.
2. Signal breakdown
* +1 Concrete out of bounds read: `acpi_ut_walk_aml_resources()` can access AML descriptor fields and calculate descriptor length before confirming that the remaining AML buffer is sufficiently large.
* +1 Firmware mediated external input surface: AML resource data is normally supplied by platform firmware or equivalent ACPI table sources. This is not direct network reachability.
* +0 Controlled reclaim, arbitrary write, type confusion, or lifetime corruption: not demonstrated.
* +0 Confidentiality impact: no read back, userspace copy, network output, or other disclosure path is established.
* +0 Integrity impact: the patch establishes validation of reads only. It does not establish an out of bounds write or modification of protected state.
* +0 Reliable kernel crash: an invalid kernel read can fault, but the supplied patch does not demonstrate a reliable panic or host wide crash.
* +0 Local unprivileged trigger: not established. The input may originate from firmware or privileged ACPI table injection mechanisms.
* +0 Remote reachability: not established.
* No privilege penalty was applied. The supplied evidence does not positively establish that host administrator privilege is required for every possible triggering path.
* No race or niche subsystem penalty was applied. This is not a race, and ACPICA itself is broadly deployed even though attacker control of AML is not established.
3. Reachability analysis
The vulnerable parser consumes AML resource descriptors associated with ACPI firmware tables and ACPI method evaluation. A malicious platform firmware image, malicious virtual firmware environment, or a privileged mechanism that injects or overrides ACPI tables could provide a truncated descriptor.
The supplied patch does not establish that an ordinary local user can supply malformed AML resources to this parser. It also does not establish that host administrator privileges are always required, because the full set of AML providers and evaluation call sites is not included. Therefore HostAdminRequired is UNKNOWN rather than YES or NO.
No relevant namespace scoped capability path is shown. There is no evidence that an attacker-created user namespace or network namespace can perform the complete malformed AML injection and evaluation sequence. NamespaceScopedPrivilege is UNKNOWN.
No direct network service, packet parser, remotely exposed protocol listener, special hardware requirement, or timing race is established by the supplied evidence.
4. Primitive and severity interpretation
The established primitive is an out of bounds read during AML resource descriptor parsing. Before the fix, a truncated small descriptor, truncated large descriptor, or descriptor with a claimed length exceeding the remaining AML buffer could cause ACPICA to inspect bytes beyond `end_aml` or pass an invalid descriptor range into subsequent processing.
This is not a UAF, double free, refcount issue, active object lifetime violation, or ownership violation. It is also not an established out of bounds write. The patch adds length checks before field accesses and before accepting the descriptor length, which supports a read bounds validation interpretation.
The appropriate classification is CLASS_C because the demonstrated behavior is invalid state handling with a possible kernel fault or DoS outcome. The patch does not establish meaningful exploitation leverage beyond the invalid read. A confidentiality consequence is possible only as an unsupported theoretical outcome unless a caller copies parsed data to an attacker-visible interface. Integrity impact, privilege escalation, controlled memory corruption, and arbitrary kernel read or write are not established.
ImportantCandidate is NO because no Class A primitive or meaningful unresolved Class B lifetime or corruption primitive exists. AutoDowngradeAllowed is YES because the available evidence supports a constrained invalid-read issue without a demonstrated reusable corruption, authorization bypass, disclosure path, or boundary violation.
5. One-sentence report phrase
An insufficient bounds check in ACPICA AML resource parsing can cause an out of bounds kernel read when malformed ACPI resource descriptors are evaluated, potentially causing a kernel fault or denial of service.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
The patch fixes a concrete kernel out of bounds read, but the supplied context does not show which AML sources are attacker controlled in the evaluated deployment or whether a reachable caller can expose parsed data.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: ACPICA: Enhance buffer validation in acpi_ut_walk_aml_resources() [ Upstream
Commit: f65e2ef7ccca11dc874f48aff996a6a26528f8e7
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f65e2ef7ccca11dc874f48aff996a6a26528f8e7
Changed files:
drivers/acpi/acpica/utresrc.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=f65e2ef7ccca11dc874f48aff996a6a26528f8e7
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-97445 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97445
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: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: unknown
Paranoid ActionableScore: 2
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 [email protected] (and both
send reply to CVE record itself too and see "reply" button below for howto reply).
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