[CVE-2026-80764][MODERATE 7.0] Bluetooth: hci_event: fix LE list UAF on reset

[CVE-2026-80764][MODERATE 7.0] Bluetooth: hci_event: fix LE list UAF on reset

[AL-KERNEL]

CVE: CVE-2026-80764
Priority: MODERATE 7.0
AL-KERNEL base severity: MODERATE
KPANIC flag: NO
Patch: Bluetooth: hci_event: fix LE list UAF on reset
Commit: 8e68c380290b1dd64a0a512ce66d0264130c46ed
Upstream patch: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8e68c380290b1dd64a0a512ce66d0264130c46ed
Original CVE announcement: https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80764
Analysis date: Fri, 04 Sep 2026 12:29:43 -0400
ActionableScore: 5
ActionableScore lower bound: 3
Actionable bucket: Actionable Moderate at minimum
Manual review required: YES

Summary:
No one-sentence report phrase was found.

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

The original Linux kernel CVE announcement for CVE-2026-80764 is available here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80764

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.

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

CVE-2026-80764	MODERATE	https://www.kernelcve.org/list/?q=CVE-2026-80764 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:N/A:H';*CWE-416;CWE-362;CWE-667;Other CVSS 'AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H';BEST CVSS score: '6.3';DESCR 'A race in Bluetooth hci_cc_reset can clear LE accept and resolving list entries without holding hdev lock while a debugfs reader is walking the same lists. This creates a use after free where white_list_show may read fields from a freed entry and may follow a stale next pointer, leading to a kernel crash and possible stale heap data exposure. For the CVSS the PR:L is used for the higher paranoid scenario because a local user or service account with access to Bluetooth debugfs reads and ability to trigger or race controller reset could reach the vulnerable path without full host administrator privileges in some deployments. The issue is not directly network reachable because it depends on local debugfs access and Bluetooth controller reset handling rather than remote packet processing. Impact is at least local denial of service via kernel crash, with possible confidentiality impact from stale kernel heap reads. No clear integrity impact or privilege escalation primitive is proven by the patch context.';YES REQUIRES MANUAL CHECK; ,and ActionableScore result is Actionable Moderate at minimum (with actual score 4)	YES	REMOTE READ LOCK DANGER UAF NETWORK DEBUGFS  LOWERED_FROM_HIGH_BASED_ON_GUESSCVSS  DECREASED_TO_MODERATEREG_BASED_ON_FALSEPOSCHECKOFKP	NO	NO	checked

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

ActionableScore=5
ActionableScoreLower=3

1. ActionableScore
* Conservative score: 3
* Paranoid score: 5
* Final recommended bucket: **Actionable Moderate at minimum**::

2. Signal breakdown
* Memory corruption, weak primitive: +1. The patch and KASAN trace show a real slab use-after-free in `white_list_show`, but only a read-side stale list entry traversal is demonstrated.
* Real lifetime corruption: +1. `hci_cc_reset()` can `list_del()` and `kfree()` LE list entries while a debugfs reader is walking the same list.
* Reliable kernel crash / strong DoS: +1. KASAN reports slab-use-after-free and stale `next` pointer traversal can plausibly crash the kernel.
* Confidentiality impact plausible: +1 in paranoid scoring. The debugfs reader may read fields from freed heap memory, so stale kernel heap disclosure is plausible, though not proven as a controlled info leak.
* Local unprivileged or reduced-privilege trigger: +1 in paranoid scoring. This depends on deployments where Bluetooth debugfs/controller access is delegated to a local service account or reduced-privilege root context.
* Hard or unreliable race: -1. Triggering requires timing between reset completion and debugfs list traversal.
* Requires admin/root in typical deployments: -2 conservative. Debugfs access and Bluetooth controller reset are commonly root/admin controlled.

3. Reachability analysis
The bug is local, not directly network reachable. A remote Bluetooth peer is not enough by itself because the demonstrated UAF requires a local debugfs read racing with local controller reset handling. In typical deployments, debugfs is either not mounted or restricted to root, and reset/control operations are administrative, so the conservative interpretation is privileged local DoS. In less strict deployments, container root, a Bluetooth management service, test tooling, or delegated debugfs access may reduce the practical privilege requirement to PR:L, which is why the paranoid score is higher.

4. Severity interpretation
This is not an ordinary cleanup bug because the patch fixes a real UAF with a KASAN report. It also is not a strong Important candidate by default because the demonstrated primitive is read-side UAF during debugfs traversal, with no shown attacker-controlled reclaim, write-after-free, type confusion, callback control, or refcount takeover. Realistic impact is local kernel crash. Paranoid impact includes possible stale heap data exposure and therefore should not be auto-closed without review.

5. One-sentence report phrase
A race in Bluetooth hci_cc_reset can free LE accept or resolving list entries while a debugfs reader is walking them, causing a local use-after-free with kernel crash risk and possible stale heap data exposure.

6. Manual review recommendation
MANUAL CHECK REQUIRED. YES REQUIRES MANUAL CHECK because this is a real race-based kernel UAF, but the currently supported primitive is weak and local rather than a demonstrated privilege escalation path.

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

Patch: Bluetooth: hci_event: fix LE list UAF on reset
Commit: 8e68c380290b1dd64a0a512ce66d0264130c46ed
Upstream URL: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=8e68c380290b1dd64a0a512ce66d0264130c46ed

Commit description:

hci_cc_reset() clears the LE accept and resolving lists without taking
hdev->lock. Other command-complete handlers serialize updates to these
lists with that lock, and the debugfs readers hold it while walking them.

This permits the reset completion and a debugfs read to interleave as
follows:

  hci_rx_work                 debugfs reader
  -----------                 --------------
                              lock hdev->lock
                              fetch current entry
  list_del(entry)
  kfree(entry)
                              read entry fields

The reader then dereferences a freed list entry and may follow its stale
next pointer.

KASAN reported:

  BUG: KASAN: slab-use-after-free in white_list_show+0x15f/0x180
  Read of size 1 at addr ffff8881015dab16 by task poc/95

  Call Trace:
   white_list_show+0x15f/0x180
   seq_read_iter+0x3ff/0x1190
   seq_read+0x267/0x3d0
   vfs_read+0x177/0xa20
   ksys_read+0xf7/0x1c0

  Allocated by task 91:
   hci_bdaddr_list_add+0x1a6/0x3a0
   hci_cc_le_add_to_accept_list+0xab/0x140
   hci_cmd_complete_evt+0x26c/0x9a0
   hci_event_packet+0x454/0xb20
   hci_rx_work+0x293/0x730

  Freed by task 90:
   kfree+0x131/0x3c0
   hci_bdaddr_list_clear+0xd8/0x160
   hci_cc_reset+0x28a/0x370
   hci_cmd_complete_evt+0x26c/0x9a0
   hci_event_packet+0x454/0xb20
   hci_rx_work+0x293/0x730

Take hdev->lock around both list clears. This matches the existing
mutation and traversal locking convention.

Fixes: a4d5504 ("Bluetooth: Clear LE white list when resetting controller")
Fixes: cfdb0c2 ("Bluetooth: Store Resolv list size")
Cc: stable@vger.kernel.org
Signed-off-by: Chengfeng Ye <nicoyip.dev@gmail.com>
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/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=8e68c380290b1dd64a0a512ce66d0264130c46ed

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

The original Linux kernel CVE announcement for CVE-2026-80764 can be found here:
https://lore.kernel.org/linux-cve-announce/?q=CVE-2026-80764

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:N/A:H
  The Best / paranoid CVSS vector: AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:H
  The Best / paranoid CVSS score: 6.3

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: 3
  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).