[CVE-2026-80763][MODERATE REGULAR] Bluetooth: hci_event: validate LE Set CIG Parameters response [ Upstream

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

CVE: CVE-2026-80763
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: Bluetooth: hci_event: validate LE Set CIG Parameters response [ Upstream
Commit: 9e05783d0bb96a7b853cc058a7c7de2dc4a62154
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9e05783d0bb96a7b853cc058a7c7de2dc4a62154
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80763
Analysis date: Fri, 04 Sep 2026 16:07:12 -0400
ActionableScore: 3
ActionableScore lower bound: 2
Actionable bucket: Borderline Moderate, manual review required but not Strong Important candidate
Manual review required: YES

Summary:
A truncated Bluetooth LE Set CIG Parameters Command Complete response can make hci_cc_le_set_cig_params read beyond the remaining skb data, causing a constrained kernel OOB read with possible DoS under malicious or malfunctioning controller conditions.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-80763 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80763

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: YES

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
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CVE-2026-80763	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-80763 CHECK WITH IMPACT FROM ORIG NN IMPORTANT	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-126;CWE-130;Other CVSS 'AV:P/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:L';BEST CVSS score: '5.3';DESCR 'Bluetooth hci_event accepts LE Set CIG Parameters Command Complete data where the fixed response was validated but the trailing handle array length was not checked. A malformed or truncated response from a malfunctioning or malicious controller can make hci_cc_le_set_cig_params read beyond the skb data while processing rp num_handles and rp handle entries. For the CVSS the PR:L is used in the paranoid score because a practical software trigger would normally require a local process with Bluetooth management or HCI injection capability, while the base hardware oriented scenario is closer to a malicious controller with physical presence. The issue is not directly network reachable over IP and is not normally triggerable by a remote Bluetooth peer alone. Impact is primarily denial of service or invalid kernel state from an out-of-bounds read, with at most limited confidentiality concern and no supported privilege escalation primitive.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline Moderate, manual review required but not Strong Important candidate (with actual score 3)	YES	REMOTE SIMPLEFIX NETWORK SKB  LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN4	YES	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=3
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 3
* Final recommended bucket: **Borderline Moderate, manual review required but not Strong Important candidate**::

## 2. Signal breakdown

* Firmware-mediated external influence: +1. The malformed input is a truncated HCI Command Complete response from a malfunctioning or malicious Bluetooth controller.
* Weak or limited memory-safety primitive: +1. The bug is an out-of-bounds read past skb data due to trusting `num_handles` without checking the remaining skb length.
* Availability concern in paranoid score: +1. The OOB read can plausibly produce invalid kernel state, warning, sanitizer report, or crash, but the patch does not show a strong reliable panic path.
* No strong LPE signal: +0. There is no shown UAF reclaim, write primitive, object replacement, type confusion, callback control, or refcount takeover.
* No direct remote-network signal: +0. This is not IP-network reachable and is not clearly triggerable by an ordinary remote Bluetooth peer.
* No confidentiality score in conservative result: +0. Although this is an OOB read, no user-visible disclosure path is shown.

## 3. Reachability analysis

The most direct trigger is a malformed response from the Bluetooth controller to the host. That makes the main attacker model firmware-mediated or malicious-device based, not ordinary remote network access. A software trigger may be possible only for a local process that can inject or emulate HCI controller events, which normally requires elevated Bluetooth management or HCI privileges. Namespaces do not obviously make this broadly unprivileged in typical deployments. The affected Bluetooth CIS/CIG path is not as broadly exposed as core packet networking.

## 4. Severity interpretation

This behaves like a constrained kernel OOB read with possible DoS, not like a strong memory-corruption or privilege-escalation issue. The theoretical risk is higher than a pure correctness fix because kernel code reads beyond skb bounds based on controller-supplied length metadata. Realistic exploitation evidence is limited because the patch shows no write primitive, no information leak path, and no practical LPE chain.

## 5. One-sentence report phrase

A truncated Bluetooth LE Set CIG Parameters Command Complete response can make hci_cc_le_set_cig_params read beyond the remaining skb data, causing a constrained kernel OOB read with possible DoS under malicious or malfunctioning controller conditions.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Manual review is warranted because this is a kernel out-of-bounds read on externally supplied controller data, but current evidence supports only constrained OOB read and possible DoS rather than privilege escalation or direct remote exploitation.

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UPSTREAM PATCH SUMMARY
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Patch: Bluetooth: hci_event: validate LE Set CIG Parameters response [ Upstream
Commit: 9e05783d0bb96a7b853cc058a7c7de2dc4a62154
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=9e05783d0bb96a7b853cc058a7c7de2dc4a62154

Changed files:
  net/bluetooth/hci_event.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=9e05783d0bb96a7b853cc058a7c7de2dc4a62154

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

The original Linux kernel CVE announcement for CVE-2026-80763 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80763

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:R/S:U/C:L/I:N/A:L
  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: 2
  Paranoid ActionableScore: 3

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).