[CVE-2026-68394][MODERATE REGULAR] Bluetooth: MGMT: revalidate LOAD_CONN_PARAM queued update [ Upstream

[CVE-2026-68394][MODERATE REGULAR] Bluetooth: MGMT: revalidate LOAD_CONN_PARAM queued update [ Upstream

[AL-KERNEL]

CVE: CVE-2026-68394
Priority: MODERATE REGULAR
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: Bluetooth: MGMT: revalidate LOAD_CONN_PARAM queued update [ Upstream
Commit: 65ce6fe1b92112ba9064ded932c03180da3dd230
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=65ce6fe1b92112ba9064ded932c03180da3dd230
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68394
Analysis date: Mon, 10 Aug 2026 15:34:53 -0400
ActionableScore: 4
ActionableScore lower bound: 1
Actionable bucket: Borderline, manual review required. Actionable Moderate candidate, not an Important by default
Manual review required: YES

Summary:
A race in Bluetooth MGMT LOAD_CONN_PARAM can leave queued work holding a freed hci_conn_params pointer, causing a slab use after free in conn_update_sync and a local kernel crash, with practical triggering normally requiring Bluetooth management privileges.

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

The original Linux kernel CVE announcement for CVE-2026-68394 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68394

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.

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

CVE-2026-68394	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:L/I:L/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: '5.8';DESCR 'Bluetooth MGMT LOAD_CONN_PARAM can queue a connection parameter update with a borrowed hci_conn_params pointer while a later request can remove and free the same entry before hci_cmd_sync_work runs. This creates a race based slab use after free in conn_update_sync when the queued callback reads the freed object. For the CVSS the PR:L is used for the paranoid score because a local process with delegated CAP_NET_ADMIN or Bluetooth management control may be sufficient in containerized or service based deployments, although normal host administration often maps this to PR:H. The issue is not network reachable over IP and is triggered through a local Bluetooth management socket, with a connected LE central connection needed for the update path. Impact is at least local denial of service via kernel crash and in worst case may allow limited confidentiality or integrity impact due to memory corruption and should be reviewed manually.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Borderline, manual review required. Actionable Moderate candidate, not an Important by default (with actual score 3)	YES	REMOTE READ DANGER UAF NETWORK  LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	YES	NO	checked

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

ActionableScore=4
ActionableScoreLower=1

## 1. ActionableScore

* Conservative score: 1
* Paranoid score: 4
* Final recommended bucket: **Borderline, manual review required. Actionable Moderate candidate, not an Important by default**::

## 2. Signal breakdown

Paranoid score signals:

* Memory corruption, weak primitive: +1. Confirmed KASAN slab-use-after-free, but the stale access is a read of an old `hci_conn_params` object and no reclaim, overwrite, type confusion, or callback control is shown.
* Real lifetime corruption: +1. The queued work kept a borrowed pointer that could be freed by a later `LOAD_CONN_PARAM`.
* Reliable kernel crash / strong DoS: +1. The report shows a reproducible KASAN UAF in `conn_update_sync()` from `hci_cmd_sync_work`.
* Availability impact realistic: +1. A kernel UAF in Bluetooth workqueue context can realistically crash or destabilize the host.
* Requires hard timing / race: 0. Although this is a race, the async queued work model gives a natural trigger window, so I would not subtract strongly.
* Requires admin/root/CAP_NET_ADMIN in typical deployments: conservative -2. Bluetooth MGMT operations are normally privileged.
* Privilege penalty refinement: paranoid 0 instead of -2. In containerized or service-based deployments, Bluetooth management control may be delegated to a reduced-capability process and should not always be treated as full host root.

Not counted:

* Remote reachable: +0. This is not IP network reachable.
* Strong LPE plausibility: +0. No attacker-controlled reclaim, write-after-free, function pointer control, refcount takeover, or object replacement is demonstrated.
* Confidentiality / integrity impact: +0 in ActionableScore. The UAF class justifies manual review, but the patch only shows a stale read and crash-oriented evidence.

## 3. Reachability analysis

The trigger is local through the Bluetooth MGMT socket using `MGMT_OP_LOAD_CONN_PARAM`. A realistic trigger needs Bluetooth enabled, an HCI device, and an existing LE central connection whose parameters are updated while another request removes the queued parameter entry. In typical host deployments this requires privileged Bluetooth management access, commonly equivalent to `CAP_NET_ADMIN` or a privileged Bluetooth service. Namespaces or service delegation can lower the practical privilege boundary, so the paranoid score treats reduced-capability Bluetooth control as less than full host-root.

## 4. Severity interpretation

This behaves like an actionable Moderate / manual-review UAF rather than a clear Important-class vulnerability. The theoretical concern is memory corruption from a real stale pointer lifetime bug, but the demonstrated primitive is a race-dependent stale read of freed parameter data, with no shown attacker-controlled reclaim or write primitive. Realistic impact is local kernel crash or instability. LPE is not excluded by bug class, but is not strongly supported by this patch alone.

## 5. One-sentence report phrase

A race in Bluetooth MGMT LOAD_CONN_PARAM can leave queued work holding a freed hci_conn_params pointer, causing a slab use after free in conn_update_sync and a local kernel crash, with practical triggering normally requiring Bluetooth management privileges.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Confirmed KASAN slab-use-after-free and asynchronous lifetime bugs should not be auto-closed, even though the currently demonstrated impact is mainly local DoS and the exploitation path does not show a strong LPE primitive.

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

Patch: Bluetooth: MGMT: revalidate LOAD_CONN_PARAM queued update [ Upstream
Commit: 65ce6fe1b92112ba9064ded932c03180da3dd230
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=65ce6fe1b92112ba9064ded932c03180da3dd230

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=65ce6fe1b92112ba9064ded932c03180da3dd230

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

The original Linux kernel CVE announcement for CVE-2026-68394 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-68394

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:L/I:L/A:H
  The Best / paranoid CVSS score: 5.8

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: 4

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).