[CVE-2026-68392][MODERATE 7.0] Bluetooth: mgmt: fix locking in unpair_device/disconnect_sync [ Upstream

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

CVE: CVE-2026-68392
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: Bluetooth: mgmt: fix locking in unpair_device/disconnect_sync [ Upstream
Commit: 8bc83f9ef6789571f399ff631a2a14a12b6d8585
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8bc83f9ef6789571f399ff631a2a14a12b6d8585
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68392
Analysis date: Mon, 10 Aug 2026 19:40:38 -0400
ActionableScore: 5
ActionableScore lower bound: 1
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
Bluetooth mgmt disconnect and unpair paths could use an hci_conn pointer after its lifetime ended due to missing lock and reference protection, allowing a local management client and possibly a nearby peer assisted race to trigger a kernel UAF and DoS.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-68392 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68392

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 7.0
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-2026-68392	MODERATE	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:H/I:H/A:H';*CWE-416;CWE-362;CWE-667;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H';BEST CVSS score: '7';DESCR 'Bluetooth mgmt unpair_device and disconnect_sync can look up an hci_conn pointer without holding the device lock long enough or taking a reference before using it. A concurrent connection teardown can free the RCU protected object before hci_abort_conn uses it, creating a race based UAF in the kernel Bluetooth control path. For the CVSS the PR:L is used for the paranoid score because the typical interface is local management control, but some systems expose disconnect or unpair actions through bluetoothd, desktop policy, service accounts, or delegated CAP_NET_ADMIN rather than full root. The issue is not directly network reachable through ordinary Bluetooth traffic alone, although a nearby Bluetooth peer may help create timing around connection teardown. Impact is at least local denial of service via kernel crash and in the worst case may allow confidentiality or integrity impact because a freed hci_conn object can be used after lifetime end.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 3)	YES	REMOTE LOCK UAF NETWORK  DECREASED_TO_MODERATE70_BASED_ON_ACTIONABLESCORELOWERTHAN7 DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	YES	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=5
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative signals:

* Memory corruption, weak primitive: +1. The patch explicitly fixes a possible UAF from dereferencing an RCU protected hci_conn pointer outside a valid lifetime protected section.
* Real lifetime corruption: +1. The fix adds hci_dev_lock plus hci_conn_get and hci_conn_put, which is a clear object lifetime protection fix.
* Reliable kernel crash / strong DoS: +1. A stale hci_conn passed to hci_abort_conn can plausibly crash the kernel.
* Broad/common deployed exposure: +1. Bluetooth is common on desktops, laptops, phones, and some embedded systems, although the mgmt path is not always exposed to untrusted users.
* Hard or unreliable race: -1. The issue depends on a race between disconnect or unpair handling and concurrent connection teardown.
* Requires admin/root/CAP_NET_ADMIN in typical deployments: -2. Direct Bluetooth mgmt socket operations are normally privileged or mediated by bluetoothd.

Paranoid additional interpretation:

* Local unprivileged trigger: +1. In some desktop or appliance deployments, unpair or disconnect actions may be reachable through bluetoothd, desktop policy, a service account, or delegated CAP_NET_ADMIN rather than full host root.
* Firmware-mediated or external peer influence: +1. A nearby Bluetooth peer cannot directly invoke the mgmt command, but can influence connection lifetime and teardown timing, which may help trigger the race.

Not counted:

* Strong LPE plausibility: +0. The patch shows UAF risk, but not attacker-controlled reclaim, object replacement, callback control, arbitrary write, or refcount takeover.
* Confidentiality and integrity impact: +0 for actionable scoring. They remain theoretical only.
* Strong memory corruption primitive: +0. This is treated under the race-UAF downgrade rule as a weak primitive.

## 3. Reachability analysis

The direct trigger is local Bluetooth management control, specifically unpair_device_sync or disconnect_sync. In the conservative model this requires CAP_NET_ADMIN or an equivalent privileged bluetooth management path, so the lower score is low.

The paranoid model is more actionable because real systems often expose Bluetooth operations through bluetoothd or desktop policy. A local user may be able to request disconnect or unpair without full root privileges, depending on policy. A nearby Bluetooth peer is not sufficient by itself to exploit the bug, but it may affect connection teardown timing and make the race more reachable.

The path is not directly network reachable in the normal IP sense. It is local control plane plus possible nearby Bluetooth peer timing influence.

## 4. Severity interpretation

This behaves like an Actionable Moderate issue rather than an ordinary low priority cleanup, because the patch explicitly fixes a UAF class lifetime bug in kernel Bluetooth connection handling.

It is not a strong Important candidate on the evidence provided. The realistic demonstrated impact is kernel crash or DoS. Privilege escalation is theoretically possible for some UAF bugs, but this patch does not show a controlled reclaim primitive, writable stale object replacement, type confusion, callback dispatch, or arbitrary write.

## 5. One-sentence report phrase

Bluetooth mgmt disconnect and unpair paths could use an hci_conn pointer after its lifetime ended due to missing lock and reference protection, allowing a local management client and possibly a nearby peer assisted race to trigger a kernel UAF and DoS.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

The patch explicitly mentions UAF and fixes locking plus refcount lifetime handling around hci_conn. Even though the current evidence mainly supports DoS, kernel lifetime bugs in a common subsystem should not be auto-closed without checking real bluetoothd policy exposure and whether stale hci_conn reuse can be influenced.

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

Patch: Bluetooth: mgmt: fix locking in unpair_device/disconnect_sync [ Upstream
Commit: 8bc83f9ef6789571f399ff631a2a14a12b6d8585
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8bc83f9ef6789571f399ff631a2a14a12b6d8585

Changed files:
  net/bluetooth/mgmt.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=8bc83f9ef6789571f399ff631a2a14a12b6d8585

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

The original Linux kernel CVE announcement for CVE-2026-68392 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68392

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: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: 1
  Paranoid ActionableScore: 5

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 7.0

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).