[CVE-2026-74511][MODERATE 7.0] Bluetooth: mgmt: fix pending command UAF in EIR updates

[CVE-2026-74511][MODERATE 7.0] Bluetooth: mgmt: fix pending command UAF in EIR updates

[AL-KERNEL]

CVE: CVE-2026-74511
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: Bluetooth: mgmt: fix pending command UAF in EIR updates
Commit: a9e7c2609b0cb3fb4b4ba9f66dd8727d33205967
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a9e7c2609b0cb3fb4b4ba9f66dd8727d33205967
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74511
Analysis date: Sat, 15 Aug 2026 15:17:00 -0400
ActionableScore: 5
ActionableScore lower bound: 2
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
A race in Bluetooth management EIR updates can cause a UAF when pending commands or UUID entries are freed while being inspected, allowing a local management-capable attacker to crash the kernel and requiring manual review for possible memory-corruption impact.

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ABOUT THIS REPORT
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The original Linux kernel CVE announcement for CVE-2026-74511 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74511

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-2026-74511	MODERATE	CHECK WITH IMPACT FROM ORIG NN LOW	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:L/I:L/A:H';BEST CVSS score: '7';DESCR 'A race in Bluetooth mgmt pending command handling can expose a UAF because pending_eir_or_class scans the hdev mgmt_pending list without holding mgmt_pending_lock. A racing command completion can remove and free a pending command while it is still being inspected, and SET_LOCAL_NAME can rebuild EIR while UUID entries are being added or removed. An attacker with local access to Bluetooth management operations could try to race SET_LOCAL_NAME with ADD_UUID or REMOVE_UUID on a powered BR/EDR controller, causing a kernel crash and potentially memory corruption. For the CVSS the PR:L is used for the paranoid score because a non root local user may be able to reach these operations through a privileged Bluetooth service or delegated policy, although direct kernel mgmt socket access often requires CAP_NET_ADMIN. The issue is not directly network reachable over IP and is not triggered by normal Bluetooth radio traffic alone. Impact is at least local denial of service via kernel crash and in the paranoid case may include confidentiality and integrity impact due to UAF memory corruption.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4)	YES	REMOTE LOCK UAF NETWORK HARDWARE  DECREASED_TO_MODERATEREG_BASED_ON_ACTIONABLESCORELESSTHAN5	YES	NO	checked

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ACTIONABLESCORE ANALYSIS
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ActionableScore=5
ActionableScoreLower=2

## 1. ActionableScore

* Conservative score: 2
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**::

## 2. Signal breakdown

Conservative scoring:

* Memory corruption, weak or indirect corruption candidate: +1
  The patch and commit message explicitly describe a race leading to use-after-free in the Bluetooth management pending-command list and possible EIR rebuild while UUID entries are being removed.
* Real lifetime corruption: +1
  The bug is a real object lifetime issue involving freed pending commands or UUID-related objects.
* Reliable kernel crash / strong DoS: +1
  A UAF in list traversal or EIR construction can realistically crash the kernel.
* Broad/common subsystem exposure on affected systems: +1
  Bluetooth management is common on desktop, laptop, and embedded systems with Bluetooth enabled.
* Privileged kernel/device-management memory corruption path: +1
  The corruption is in Bluetooth controller management code and affects kernel-owned management objects.
* Hard or unreliable race / special timing required: -1
  Triggering requires racing asynchronous management command completion and EIR/name/UUID updates.
* Requires CAP_NET_ADMIN or privileged Bluetooth management access in typical direct use: -2
  Direct Bluetooth management socket operations are normally privileged.

Conservative total: 2

Paranoid scoring:

* Local unprivileged trigger: +1
  In some real deployments, non-root local users may influence Bluetooth management operations indirectly through bluetoothd, desktop policy, or delegated service interfaces.
* Memory corruption, weak or indirect corruption candidate: +1
  This is a race-dependent UAF without a demonstrated reclaim, write-after-free, callback hijack, or arbitrary write primitive.
* Real lifetime corruption: +1
  The bug involves freed pending-command or UUID-list objects being observed by concurrent logic.
* Reliable kernel crash / strong DoS: +1
  Kernel crash is a realistic outcome.
* Broad/common subsystem exposure on affected systems: +1
  Bluetooth is commonly enabled on many client systems.
* Privileged kernel/device-management memory corruption path: +1
  The affected path is trusted kernel Bluetooth management state.
* Hard or unreliable race / special timing required: -1
  The race requirement reduces practical reliability.

Paranoid total: 5

## 3. Reachability analysis

The direct trigger is local Bluetooth management control, especially racing `MGMT_OP_SET_LOCAL_NAME` with UUID-changing operations such as `MGMT_OP_ADD_UUID` or `MGMT_OP_REMOVE_UUID` on a powered BR/EDR-capable controller. Direct access usually requires privileged Bluetooth management permissions, commonly CAP_NET_ADMIN or a privileged daemon such as bluetoothd.

Namespace and container effects are deployment-dependent. If Bluetooth management is exposed only to host root or a tightly confined daemon, conservative severity is lower. If a local user can reach these operations through desktop policy, bluetoothd D-Bus workflows, delegated service APIs, or reduced-capability service accounts, PR:L-like reachability is plausible for triage.

This is not remotely reachable over IP and is not triggered by ordinary Bluetooth radio traffic alone.

## 4. Severity interpretation

This behaves like an Actionable Moderate issue under paranoid triage, not an ordinary auto-close Moderate. The patch supports a real race-dependent UAF, but does not show attacker-controlled reclaim, arbitrary write, function pointer control, or a demonstrated LPE primitive. Therefore the realistic impact is kernel crash / local DoS, while the worst-case concern is limited kernel memory corruption requiring manual review.

Theoretical privilege escalation cannot be ruled out purely because the bug is a kernel UAF, but the available patch context supports only weak LPE concern, not a strong Important classification by itself.

## 5. One-sentence report phrase

A race in Bluetooth management EIR updates can cause a UAF when pending commands or UUID entries are freed while being inspected, allowing a local management-capable attacker to crash the kernel and requiring manual review for possible memory-corruption impact.

## 6. Manual review recommendation

MANUAL CHECK REQUIRED

Reason: the issue is an explicitly described kernel UAF in a race-sensitive Bluetooth management path. Even though no strong reclaim or write primitive is shown, kernel lifetime bugs of this class should not be auto-closed without manual review.

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

Patch: Bluetooth: mgmt: fix pending command UAF in EIR updates
Commit: a9e7c2609b0cb3fb4b4ba9f66dd8727d33205967
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a9e7c2609b0cb3fb4b4ba9f66dd8727d33205967

Commit description:

MGMT_OP_SET_LOCAL_NAME is handled asynchronously on powered controllers
and can run set_name_sync().  When the controller is BR/EDR capable,
set_name_sync() updates the local name and then rebuilds EIR data through
eir_create().  The EIR builder walks hdev->uuids, but the UUID list can
be changed and entries can be freed by MGMT_OP_ADD_UUID and
MGMT_OP_REMOVE_UUID.

pending_eir_or_class() is meant to serialize management commands that
can change EIR or the class of device, but it did not include
MGMT_OP_SET_LOCAL_NAME.  In addition, it walked hdev->mgmt_pending
without hdev->mgmt_pending_lock even though pending commands are added
and removed under that mutex.  A racing command completion can therefore
remove and free a pending command while pending_eir_or_class() is still
inspecting it, leading to a use-after-free in the pending-command list or
allowing a local name update to rebuild EIR while UUID entries are being
removed.

Take hdev->mgmt_pending_lock while scanning hdev->mgmt_pending and treat
MGMT_OP_SET_LOCAL_NAME as an EIR/class-affecting pending command on the
powered asynchronous path.  Check for a conflicting pending command before
copying the new short name so a rejected SET_LOCAL_NAME request does not
modify hdev->short_name.

Fixes: 6fe26f6 ("Bluetooth: MGMT: Protect mgmt_pending list with its own lock")
Cc: stable@vger.kernel.org
Reported-by: Vega <vega@nebusec.ai>
Assisted-by: Codex:gpt-5.4
Signed-off-by: Zihan Xi <zihanx@nebusec.ai>
Signed-off-by: Ren Wei <enjou1224z@gmail.com>
Reported-by: Vega <vega@nebusec.ai>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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=a9e7c2609b0cb3fb4b4ba9f66dd8727d33205967

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

The original Linux kernel CVE announcement for CVE-2026-74511 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-74511

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: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: 2
  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).