---
id: CVE-2026-43334
title: >-
  Bluetooth: SMP: force responder MITM requirements before building the pairing
  response
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  Bluetooth: SMP: force responder MITM requirements before building the pairing
  response


  smp_cmd_pairing_req() currently builds the pairing response from the

  initiator a…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 <
    425a22c5373d4e1b46492ab869074ebeeade61f3
  - >-
    Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 <
    7ab69426e7ecbd18a222ee2ec87ca612d30197d7
  - >-
    Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 <
    01bb4045d2306c266178f49ce0c3576d237a3040
  - >-
    Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 <
    91649c02c1baaa18cedf7fb425fa1f0f852c8183
  - >-
    Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 <
    c8ff0ca6508535bccabd81c5c9dcc63de8a3d4fb
  - >-
    Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 <
    fa14e0e19820b1bbdb42185c9c4efa950bcffef9
  - >-
    Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 <
    ec17efb1ef91506cfd17a77692eaf4bbacb520ea
  - >-
    Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 <
    d05111bfe37bfd8bd4d2dfe6675d6bdeef43f7c7
  - Linux 3.3
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:16:29.705112Z'
published: '2026-05-08'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:20:39.188Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-43334'
references:
  - url: 'https://git.kernel.org/stable/c/425a22c5373d4e1b46492ab869074ebeeade61f3'
  - url: 'https://git.kernel.org/stable/c/7ab69426e7ecbd18a222ee2ec87ca612d30197d7'
  - url: 'https://git.kernel.org/stable/c/01bb4045d2306c266178f49ce0c3576d237a3040'
  - url: 'https://git.kernel.org/stable/c/91649c02c1baaa18cedf7fb425fa1f0f852c8183'
  - url: 'https://git.kernel.org/stable/c/c8ff0ca6508535bccabd81c5c9dcc63de8a3d4fb'
  - url: 'https://git.kernel.org/stable/c/fa14e0e19820b1bbdb42185c9c4efa950bcffef9'
  - url: 'https://git.kernel.org/stable/c/ec17efb1ef91506cfd17a77692eaf4bbacb520ea'
  - url: 'https://git.kernel.org/stable/c/d05111bfe37bfd8bd4d2dfe6675d6bdeef43f7c7'
tags:
  - cve.org
epss: 0.00252
epssPercentile: 0.15574
ingestedAt: '2026-10-16T17:24:46.692Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: SMP: force responder MITM requirements before building the pairing response

smp_cmd_pairing_req() currently builds the pairing response from the
initiator auth_req before enforcing the local BT_SECURITY_HIGH
requirement. If the initiator omits SMP_AUTH_MITM, the response can
also omit it even though the local side still requires MITM.

tk_request() then sees an auth value without SMP_AUTH_MITM and may
select JUST_CFM, making method selection inconsistent with the pairing
policy the responder already enforces.

When the local side requires HIGH security, first verify that MITM can
be achieved from the IO capabilities and then force SMP_AUTH_MITM in the
response in both rsp.auth_req and auth. This keeps the responder auth bits
and later method selection aligned.

## Affected

- `Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 < 425a22c5373d4e1b46492ab869074ebeeade61f3`
- `Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 < 7ab69426e7ecbd18a222ee2ec87ca612d30197d7`
- `Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 < 01bb4045d2306c266178f49ce0c3576d237a3040`
- `Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 < 91649c02c1baaa18cedf7fb425fa1f0f852c8183`
- `Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 < c8ff0ca6508535bccabd81c5c9dcc63de8a3d4fb`
- `Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 < fa14e0e19820b1bbdb42185c9c4efa950bcffef9`
- `Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 < ec17efb1ef91506cfd17a77692eaf4bbacb520ea`
- `Linux >= 2b64d153a0cc9d2b60e47be013cde8490f16e0a5 < d05111bfe37bfd8bd4d2dfe6675d6bdeef43f7c7`
- `Linux 3.3`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.