[CVE-2026-98392][MODERATE REGULAR] Bluetooth: btintel_pcie: fix tx_handle bounds off-by-one [ Upstream

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

CVE: CVE-2026-98392
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: Bluetooth: btintel_pcie: fix tx_handle bounds off-by-one [ Upstream
Commit: 72bbd7c815ef92399b7b109977ae4669ce22ee6e
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=72bbd7c815ef92399b7b109977ae4669ce22ee6e
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98392
Analysis date: Wed, 14 Oct 2026 22:11:52 -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-2026-98392 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98392

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-2026-98392	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-98392 CHECK WITH IMPACT FROM ORIG NN MODERATE | AEGIS IMPACT MODERATE_KPANIC AEGIS_AS=1 LEGACY=MODERATE RESULT=DIFF (independent Legacy and Aegis differ; FINAL: MODERATE, Aegis: MODERATE_KPANIC)	Maybe valid. Check manually. Hints by AL-KERNEL: The best (paranoid) CVSS is 'AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H';CWE-193;CWE-129;CWE-125;*CWE-787;Other CVSS 'AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H';BEST CVSS score: '7';DESCR 'An off-by-one bounds check in btintel_pcie_msix_tx_handle allows tfd_index equal to txq count even though the last valid index is txq count minus one. The invalid index can then be used with the TX descriptor and buffer arrays, creating an out-of-bounds memory access in the PCIe TX completion path. At minimum this may crash the kernel. If the out-of-bounds buffer entry is later interpreted as a valid object or pointer, memory corruption and privilege escalation may be possible, although reliable control is not established by the provided diff. For the CVSS the PR:L reflects that a local user or process able to exercise Bluetooth TX is the most defensible attacker model. AC:H reflects the need to reach the specific invalid completion index and the absence of evidence that ordinary traffic reliably controls it. Direct remote triggering by an adjacent Bluetooth peer is not proven and requires manual source and hardware path review. Automated impact decision path. The original SimpleNet classifier selected MODERATE_KPANIC. The primary LLM estimated paranoid CVSS 7 and the production ActionableScore returned 2 with recommendation Ordinary Moderate. The production rules then evaluated CVSS thresholds and ActionableScore thresholds. Recorded rule transitions were 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 DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4. The independent weaker Aegis shadow evaluated CVSS 2.5 and ActionableScore 1 with primitive class CLASS_C and manual review RECOMMENDED. 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 2)	MAYBE	OOB SIMPLEFIX LINUS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4	-	-	checked

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

ActionableScore=2
PrimitiveClass=CLASS_C
RealUAF=NO
HostAdminRequired=UNKNOWN
NamespaceScopedPrivilege=UNKNOWN
ImportantCandidate=NO
ManualReview=RECOMMENDED
AutoDowngradeAllowed=YES
RequiresHostUID0=UNKNOWN
AuthorizationDecisionBypass=NO
ProtectedResourceImpact=NONE
B4PendingReview=NO
B4PendingConfirmed=NO

1. ActionableScore

* Raw conservative score: 2
* Conservative score: 2
* Raw paranoid score: 2
* Paranoid score: 2
* No floor or cap was applied.
* Final recommended bucket: **Ordinary Moderate**::

2. Signal breakdown

* +1 Weak or indirect corruption candidate. The off-by-one check permits `tfd_index == txq->count`, which is outside the valid range for the TX queue arrays.
* +1 Realistic kernel crash or DoS. Consuming an out-of-range TX descriptor or buffer entry in an interrupt completion path can plausibly cause an invalid access or pointer consumption.
* No strong corruption bonus. The supplied context does not show a confirmed OOB write, its payload, or the affected adjacent object.
* No firmware-mediated exposure bonus. The index appears associated with PCIe completion state, but attacker influence over the controller or firmware value is not established.
* No local-unprivileged bonus. Bluetooth TX may exercise the handler, but the evidence does not establish that an ordinary user can force the invalid index.
* No remote bonus. An adjacent Bluetooth peer is not shown to control `tfd_index`.
* No UAF, controlled reclaim, arbitrary write, information disclosure, authorization bypass, or privilege escalation is established.
* No additional availability point was awarded for the same possible crash.
* B5-R is not established. There is no confirmed retry-accumulated heap OOB write, attacker-influenced retry sequence, or demonstrated later consumption of retry-corrupted state.
* B3-PENDING and B4-PENDING do not apply.

3. Reachability analysis

The vulnerable function processes Intel Bluetooth PCIe TX completions. A local process generating Bluetooth transmissions may cause the completion handler to run, but the supplied evidence does not show who can make the completion metadata contain `tfd_index == txq->count`.

The value is apparently mediated by the PCIe device or its firmware. Direct control by a remote Bluetooth peer is not demonstrated. The complete trigger could depend on malformed firmware output, device state, or another driver bookkeeping error.

Host-admin requirements therefore remain unknown rather than proven absent or present. No namespace-scoped trigger is established. Compatible Intel PCIe Bluetooth hardware is required, but the evidence does not justify a rare-hardware penalty. This is not presented as a race.

4. Primitive and severity interpretation

The exact demonstrated defect is an unchecked one-past-the-end TX queue index. The patch establishes that `txq->count` is invalid for `urbd0s`, `tfds`, and `bufs`, but the supplied source does not show the operations performed with the indexed `tfds` or `bufs` elements.

This supports CLASS_C invalid-state and possible crash behavior. It does not establish a confirmed heap OOB write, UAF, double release, controlled overwrite, or useful disclosure primitive. RealUAF is therefore NO.

A stronger outcome would require confirming that later code writes through the invalid slot, frees an OOB-derived pointer, or otherwise consumes attacker-influenced adjacent data. Those possibilities warrant source-level review but are not scored as established primitives.

ImportantCandidate is NO because meaningful exploitation leverage beyond a possible crash is unresolved and not positively demonstrated. AutoDowngradeAllowed is YES because the available evidence supports a constrained invalid-index defect rather than a strong corruption or boundary-bypass primitive.

5. One-sentence report phrase

An off-by-one check in the Intel Bluetooth PCIe TX completion handler permits a one-past-the-end queue index and may cause an invalid descriptor or buffer access, but the supplied context does not establish a controlled OOB write or attacker-controlled trigger.

6. Manual review recommendation

MANUAL CHECK RECOMMENDED

Review all uses of `urbd0->tfd_index` after the guard, especially writes to `txq->bufs`, descriptor updates, DMA unmapping, and skb release operations, to determine whether the defect is an actual OOB write or invalid free rather than only an invalid read or crash.

7. Call-site confidence

Call-site confidence: low

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

Patch: Bluetooth: btintel_pcie: fix tx_handle bounds off-by-one [ Upstream
Commit: 72bbd7c815ef92399b7b109977ae4669ce22ee6e
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=72bbd7c815ef92399b7b109977ae4669ce22ee6e

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=72bbd7c815ef92399b7b109977ae4669ce22ee6e

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

The original Linux kernel CVE announcement for CVE-2026-98392 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-98392

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:L/UI:N/S:U/C:L/I:L/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  The Best / paranoid CVSS score: 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: 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 alexanjelausa@gmail.com (and both
send reply to CVE record itself too and see "reply" button below for howto reply).