* [CVE-2026-97453][MODERATE REGULAR] ACPICA: validate byte_count in acpi_ps_get_next_package_length() [ Upstream
@ 2026-09-24 22:06 21% AL-KERNEL
0 siblings, 0 replies; 1+ results
From: AL-KERNEL @ 2026-09-24 22:06 UTC (permalink / raw)
To: kernel-cve
CVE: CVE-2026-97453
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: ACPICA: validate byte_count in acpi_ps_get_next_package_length() [ Upstream
Commit: 780f380c66b80030379bec65bb1bd09ce6f6d9fc
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=780f380c66b80030379bec65bb1bd09ce6f6d9fc
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97453
Analysis date: Thu, 24 Sep 2026 18:06:31 -0400
ActionableScore: 1
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-2026-97453 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97453
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-2026-97453 MODERATE https://www.kernelcve.org/list/?q=CVE-2026-97453 CHECK WITH IMPACT FROM ORIG NN MODERATE Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:H';CWE-125;*CWE-20;CWE-1284;Other CVSS 'AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L';BEST CVSS score: '5.1';DESCR 'An out of bounds read in ACPICA package length parsing can occur when malformed AML declares additional PackageLength bytes beyond parser_state aml_end. The parser may read beyond the available AML buffer while decoding the package length. For the CVSS the PR:H reflects that reliable triggering normally requires control of ACPI tables or AML through firmware boot configuration or an equivalent administrative capability. The issue is not directly network reachable. Impact is primarily limited availability impact from malformed AML handling. A limited confidentiality impact and a kernel crash are conservative possibilities for the paranoid score, but the patch does not show an out of bounds write use after free or a supported privilege escalation primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1) YES DANGER SIMPLEFIX DECREASED_TO_MODERATE_REGULAR_FROM_MODERATE7_BASED_ON_GUESSCVSS_AND_CIANNH NO NO checked
======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================
ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
1. ActionableScore
* Raw conservative score: 1
* Conservative score: 1
* Raw paranoid score: 1
* Paranoid score: 1
* Final recommended bucket: **Ordinary Moderate**::
No floor or cap was applied.
2. Signal breakdown
* +1 Firmware-mediated external influence. The malformed AML input is normally supplied through ACPI tables and platform firmware. This is not direct remote reachability and does not establish that an ordinary local user can provide malicious AML.
* +0 Limited out of bounds read concern. The patch establishes that package-length decoding may read beyond `parser_state->aml_end` when the AML buffer has insufficient bytes. The patch does not establish an out of bounds write, use-after-free, object replacement, refcount corruption, or attacker-controlled target.
* +0 Reliable kernel crash not awarded. The supplied patch validates a parser boundary but does not demonstrate a panic, Oops, or reproducible crash.
* +0 Confidentiality not awarded. No path copies the bytes read past the AML boundary to userspace, network output, logs, or another attacker-visible channel.
* +0 Integrity not awarded. No write primitive or security-sensitive state modification is shown.
* +0 Remote reachability not awarded. AML is firmware or boot-configuration mediated input, not directly attacker-supplied network traffic.
* +0 Local unprivileged trigger not awarded. The supplied evidence does not show that an ordinary local user can install or override the relevant ACPI AML table.
* No host-admin penalty was applied. Host-admin-equivalent control is plausible for ACPI table override or boot configuration, but it is not positively established by the supplied patch.
* No rare-hardware or race penalty was applied. The issue is malformed-input parsing, not a timing race or a hardware-specific asynchronous condition.
3. Reachability analysis
The vulnerable operation parses AML PackageLength encoding in ACPICA. A malformed AML buffer can declare one to three additional PackageLength bytes when fewer bytes remain before `aml_end`, causing reads beyond the intended parser boundary.
The likely input source is an ACPI table provided by platform firmware, a boot-time ACPI table override, or another privileged platform configuration mechanism. The supplied evidence does not establish a complete attacker path for an ordinary user, a container user, or a namespace-scoped capability holder.
HostAdminRequired is therefore UNKNOWN rather than YES. The common requirement for firmware modification, boot configuration control, or ACPI table injection is not enough to claim a proven host-admin requirement from the patch alone. NamespaceScopedPrivilege is UNKNOWN because no namespace-aware input or capability path is shown.
There is no direct network trigger, no special runtime device interface, no demonstrated prior attacker-controlled setup, and no race requirement.
4. Primitive and severity interpretation
The exact primitive is a bounded parser out of bounds read. Before the fix, `acpi_ps_get_next_package_length()` reads `aml[0]` without first confirming at least one remaining byte, and can later read additional PackageLength bytes despite insufficient remaining AML data.
This is not a UAF, refcount bug, double release, active-object lifetime issue, or ownership violation. It is also not an out of bounds write. The patch clamps parsing to `aml_end` and returns a zero package length when the encoded byte count is invalid.
The appropriate class is CLASS_C because the established behavior is malformed parser state and a potential invalid read. The patch does not establish an independently useful memory-corruption primitive, disclosure path, privilege escalation, or security-boundary bypass.
The supplied CVSS hint allows a paranoid `C:L/I:N/A:H` interpretation, but the ActionableScore does not award confidentiality or strong availability points because neither disclosure nor crash behavior is demonstrated in the supplied evidence. The realistic operational consequence is malformed AML parsing failure, with a possible but unproven crash depending on surrounding allocation and parser state.
ImportantCandidate is NO. AutoDowngradeAllowed is YES because no meaningful unresolved corruption, lifetime, authorization, or ownership primitive remains after excluding speculative consequences.
5. One-sentence report phrase
Malformed ACPI AML PackageLength data can cause ACPICA to read beyond the parser AML boundary, but the supplied patch establishes only a limited invalid-read parser condition without a demonstrated disclosure, write, crash, or privilege-escalation primitive.
6. Manual review recommendation
MANUAL CHECK RECOMMENDED
ACPICA parses firmware-mediated input in kernel context, so callers and malformed-table error handling should be checked manually, but the available patch evidence supports only a constrained out of bounds read.
7. Call-site confidence
Call-site confidence: medium
======================================================================
UPSTREAM PATCH SUMMARY
======================================================================
Patch: ACPICA: validate byte_count in acpi_ps_get_next_package_length() [ Upstream
Commit: 780f380c66b80030379bec65bb1bd09ce6f6d9fc
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=780f380c66b80030379bec65bb1bd09ce6f6d9fc
Changed files:
drivers/acpi/acpica/psargs.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=780f380c66b80030379bec65bb1bd09ce6f6d9fc
======================================================================
DETAILED REPORT METHODOLOGY
======================================================================
The original Linux kernel CVE announcement for CVE-2026-97453 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-97453
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:L
The Best / paranoid CVSS vector: AV:L/AC:L/PR:H/UI:N/S:U/C:L/I:N/A:H
The Best / paranoid CVSS score: 5.1
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: 1
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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