[CVE-2026-93132][LOW] ACPI: RISC-V: Fix riscv_acpi_add_prt_dep() loop handling [ Upstream

[CVE-2026-93132][LOW] ACPI: RISC-V: Fix riscv_acpi_add_prt_dep() loop handling [ Upstream

[AL-KERNEL]

CVE: CVE-2026-93132
Priority: LOW
AL-KERNEL base severity: LOW
KPANIC flag: NO
Patch: ACPI: RISC-V: Fix riscv_acpi_add_prt_dep() loop handling [ Upstream
Commit: 41652ca8c6ff2b77b9780cbbb2f20f1551b9ff80
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=41652ca8c6ff2b77b9780cbbb2f20f1551b9ff80
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93132
Analysis date: Fri, 18 Sep 2026 00:55:19 -0400
ActionableScore: 0
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-2026-93132 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93132

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: LOW
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-2026-93132	LOW	https://www.kernelcve.org/list/?q=CVE-2026-93132 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:N/I:N/A:H';*CWE-835;CWE-834;CWE-703;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '4.4';DESCR 'riscv_acpi_add_prt_dep() can loop incorrectly while parsing ACPI PCI routing table entries because error paths used continue before advancing to the next entry. A malformed or problematic firmware supplied PRT entry can therefore keep the parser on the same entry and cause an availability impact during ACPI dependency setup on affected RISC-V systems. For the CVSS the PR:H is used because reliable triggering normally requires control over ACPI tables, firmware data, or another highly privileged platform configuration path. The issue is not network reachable and does not involve packet processing or a remote service. Impact is denial of service through a possible boot or initialization hang, with no evidence of memory corruption, information disclosure, or privilege escalation.';NO MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 0)  SKIP CVE-2026-93132 UNKNOWN SKIP The Fixes patch not applied yet, so unlikely that actual: url YES  NO NO unknown 	MAYBE	SIMPLEFIX  DECREASED_TO_LOW_FROM_MODERATE_BASED_ON_GUESSCVSS_AND_CIANNH	-	-	checked

======================================================================
ACTIONABLESCORE ANALYSIS
======================================================================

ActionableScore=0
PrimitiveClass=NONE
RealUAF=NO
HostAdminRequired=YES
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=NO
AutoDowngradeAllowed=YES

1. ActionableScore

* Raw conservative score: 0
* Conservative score: 0
* Raw paranoid score: 0
* Paranoid score: 0
* Final recommended bucket: **Ordinary Moderate**::

No floor or cap changed the score.

2. Signal breakdown

Positive signals:

* +1 Reliable DoS or strong availability concern. The loop can fail to advance the ACPI PRT entry pointer on error paths and may spin during ACPI dependency setup.
* +1 Firmware or platform supplied input influence. The problematic data comes from ACPI PRT or firmware supplied routing information, not from an ordinary userspace data path.

Negative signals:

* -2 Host admin or firmware level control required. Reliable triggering requires control over ACPI tables, firmware data, boot platform configuration, or equivalent privileged platform state.

Non-awarded signals:

* RealUAF not awarded. No freed object or stale post lifetime use is established.
* Memory corruption not awarded. The patch fixes loop progression, not UAF, OOB, double free, refcount misuse, type confusion, or write corruption.
* Confidentiality and integrity not awarded. No disclosure, unauthorized write, ownership bypass, or security boundary bypass is shown.
* Remote reachability not awarded. This is not packet processing and not a remotely exposed service.
* Extra availability not awarded. The possible hang is the same DoS consequence already counted.
* Race or timing penalty not applied. This is an ordered loop handling bug, not a timing race.

3. Reachability analysis

The apparent trigger is malformed or problematic ACPI PCI routing table data processed by riscv_acpi_add_prt_dep on RISC-V ACPI systems. An ordinary local user cannot normally modify ACPI firmware tables or platform routing data. Reliable attacker control therefore requires host administrator, firmware, bootloader, or platform configuration level access.

Namespace scoped privilege is not applicable. There is no evidence that a user namespace, network namespace, container capability, or delegated local capability can provide the complete trigger chain. Prior privileged setup is effectively required because the vulnerable input is firmware or platform supplied ACPI data. No network vector is established. No special race repeatability is involved.

4. Primitive and severity interpretation

The exact primitive is an infinite loop or non advancing parser state in ACPI PRT handling when error paths use continue before advancing to the next routing table entry. This is a logic bug and DoS only condition.

There is no active structured UAF, no fixed stale storage UAF, no repeated release or refcount mutation, and no cleanup destructor stale dereference. The demonstrated consequence is a possible boot or initialization hang during ACPI dependency setup. A stronger consequence such as privilege escalation or memory corruption is not supported by the patch or supplied context.

PrimitiveClass=NONE because no meaningful corruption, lifetime, ownership, authorization, or security boundary primitive is established. ImportantCandidate=NO because this is a host admin or firmware controlled DoS only condition. AutoDowngradeAllowed=YES because no unresolved kernel corruption or boundary bypass primitive would be lost by ordinary Moderate or Low-like handling.

5. One-sentence report phrase

ACPI RISC-V PRT dependency setup can enter a non advancing loop on certain error paths, causing a possible initialization hang, but reliable triggering requires firmware or host administrator level control and no memory corruption or privilege escalation primitive is established.

6. Manual review recommendation

NO MANUAL CHECK NEEDED

Reason: this is a DoS only loop handling issue with host admin or firmware level reachability and no established corruption, UAF, authorization bypass, or network exposure.

7. Call-site confidence

Call-site confidence: high

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

Patch: ACPI: RISC-V: Fix riscv_acpi_add_prt_dep() loop handling [ Upstream
Commit: 41652ca8c6ff2b77b9780cbbb2f20f1551b9ff80
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=41652ca8c6ff2b77b9780cbbb2f20f1551b9ff80

Changed files:
  drivers/acpi/riscv/irq.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=41652ca8c6ff2b77b9780cbbb2f20f1551b9ff80

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

The original Linux kernel CVE announcement for CVE-2026-93132 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-93132

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:L/PR:H/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS score: 4.4

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: 0

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: LOW
KPANIC detected for this report: NO
Published priority for this report (same as in Subject): LOW

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).