[CVE-2026-98601][MODERATE REGULAR] Bluetooth: btintel_pcie: validate device-supplied DMA indices [ Upstream

[CVE-2026-98601][MODERATE REGULAR] Bluetooth: btintel_pcie: validate device-supplied DMA indices [ Upstream

[AL-KERNEL]

CVE: CVE-2026-98601
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: Bluetooth: btintel_pcie: validate device-supplied DMA indices [ Upstream
Commit: f42cd95e679d5b78611cd2208cd1c41ad0045ffa
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f42cd95e679d5b78611cd2208cd1c41ad0045ffa
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98601
Analysis date: Sat, 24 Oct 2026 03:48:41 -0400
ActionableScore: 1
ActionableScore lower bound: unknown
Actionable bucket: Ordinary Moderate
Manual review required: NO

Summary:
A malicious PCIe Bluetooth device can supply invalid DMA queue metadata to cause an out-of-bounds buffer-table dereference or a nonterminating interrupt handler, with host DoS supported but no confirmed write primitive.

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

The original Linux kernel CVE announcement for CVE-2026-98601 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98601

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.

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AL-KERNEL CLASSIFICATION RESULT
======================================================================

CVE-2026-98601	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98601 CHECK WITH IMPACT FROM ORIG NN IMPORTANT | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=2 LEGACY=MODERATE RESULT=DIFF (final Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H';CWE-125;CWE-129;*CWE-835;Other CVSS 'AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '5.7';DESCR 'A PCIe Bluetooth device can supply an out of range RX frbd_tag through DMA and make btintel_pcie_msix_rx_handle access beyond the 64 entry rxq bufs array before dereferencing the resulting data_buf. The same device controlled DMA metadata can set cr_hia outside the queue range, making the modulo wrapped consumer index unable to reach it and causing a nonterminating MSI X handler with a potential host lockup. For the CVSS the PR:N value is used because no authenticated host privilege is required from the attached device, although exploitation requires physical PCIe device presence or control of its firmware. This is not established as remotely reachable through ordinary Bluetooth traffic. Availability impact is directly supported. Limited confidentiality or integrity impact is retained only in the paranoid vector because the downstream use of the out of bounds data_buf pointer remains security sensitive but no arbitrary read, arbitrary write, or data disclosure primitive is proven. Automated impact decision path. The original SimpleNet classifier selected IMPORTANT. The primary LLM estimated paranoid CVSS 5.7 and the production ActionableScore returned 1 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were CVSS and initial triage stage IMPORTANT to MODERATE_KPANIC because the CVSS score, vector or bug class threshold rule was applied. ActionableScore thresholds stage MODERATE_KPANIC to MODERATE because the ActionableScore threshold rule was applied. The legacy KP specialist has no review artifact for this run. The legacy FD or DH downgrade specialist has no review artifact for this run. Exact triggered rule markers were LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS and DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 and V41_INHERITED_KPANIC_PROMOTION_BLOCKED and MANUAL_REVIEW_REQUIRED. The independent weaker Aegis shadow evaluated CVSS 2.4 and ActionableScore 2 with primitive class CLASS_C and manual review REQUIRED. Its independently reconciled impact was MODERATE_KPANIC. The models disagreed but the aggregation rules retained the production result. The final reported impact is MODERATE.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Ordinary Moderate (with actual score 1)	MAYBE	WRITE OOB SIMPLEFIX ERRORPATH DMAorINTERRUPT HARDWARE LINUS  LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4 V41_INHERITED_KPANIC_PROMOTION_BLOCKED MANUAL_REVIEW_REQUIRED	-	-	checked

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

ActionableScore=1
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=NO
NamespaceScopedPrivilege=NO
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
RequiresHostUID0=NO
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw base score: 1.
* Conservative score: 1; no floor or cap applied.
* Raw paranoid score: 1.
* Paranoid score: 1; downstream confidentiality or integrity effects are not sufficiently evidenced.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Firmware-mediated external influence: device firmware controls `frbd_tag` and `cr_hia` through DMA-coherent metadata.
* +1 Weak/indirect corruption candidate: unchecked `frbd_tag` selects beyond the 64-entry `rxq->bufs[]`, producing an invalid structured pointer that is subsequently dereferenced.
* +1 Reliable strong DoS concern: an out-of-range `cr_hia` cannot equal the modulo-wrapped consumer index, permitting a nonterminating MSI-X handler and host lockup.
* -2 Physical/device prerequisite: exploitation requires a malicious attached PCIe device or control of its firmware; ordinary Bluetooth traffic is not shown to reach the defect.

Not awarded:

* No confirmed heap OOB write, arbitrary read/write, controlled target, disclosure, or protected-state modification.
* NEW52/B5-R does not apply: there is no retry-accumulated index and no confirmed OOB write.
* No extra availability point; the possible lockup is the already-counted DoS.
* No C/I points based only on possible downstream use of the invalid pointer.
* No authorization bypass or B4-PENDING path exists.

3. Reachability analysis

The evidenced attacker is a malicious PCIe Bluetooth device or compromised device firmware, not a normal local user, namespace actor, or remote Bluetooth peer. No host UID 0 or host-administrator authority is needed by that device actor. Namespace capabilities and prior namespace setup are irrelevant. Physical device presence or firmware control is the material prerequisite; no timing race is shown.

4. Primitive and severity reading

The patch shows an unchecked device-controlled array index and an independently device-controlled nonterminating queue condition. It does not show a heap write: the supplied evidence establishes invalid pointer selection/dereference, with likely crash or undefined structured access, but not a write to an identified object. This is CLASS_C rather than B5-R Class B. Important-grade leverage remains speculative, so `ImportantCandidate=NO` and automatic Moderate downgrade remains permissible, although manual confirmation of downstream `buf` consumers is recommended.

5. One-sentence report phrase

A malicious PCIe Bluetooth device can supply invalid DMA queue metadata to cause an out-of-bounds buffer-table dereference or a nonterminating interrupt handler, with host DoS supported but no confirmed write primitive.

6. Manual review advice

MANUAL CHECK RECOMMENDED

Review the omitted downstream `buf` uses to confirm that they do not turn the invalid array selection into an actual kernel write or disclosure.

7. Call-site confidence

Call-site confidence: medium

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

Patch: Bluetooth: btintel_pcie: validate device-supplied DMA indices [ Upstream
Commit: f42cd95e679d5b78611cd2208cd1c41ad0045ffa
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=f42cd95e679d5b78611cd2208cd1c41ad0045ffa

Changed files:
  drivers/bluetooth/btintel_pcie.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=f42cd95e679d5b78611cd2208cd1c41ad0045ffa

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

The original Linux kernel CVE announcement for CVE-2026-98601 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98601

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:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
  The Best / paranoid CVSS vector: AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS score: 5.7

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: 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 alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).