---
id: CVE-2026-43020
title: 'Bluetooth: MGMT: validate LTK enc_size on load'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: MGMT: validate LTK enc_size on load

  Load Long Term Keys stores the user-provided enc_size and later uses
  it to size fixed-size stack operations when replyin…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 <
    0f37d1e65c6d71ad94ccfb5c602163c525db789d
  - >-
    Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 <
    257cdb960d8ff6d60bb6461b03c814b6cf0c9e64
  - >-
    Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 <
    c34577f517b556fb6ca173d45bf7e766ae2564ce
  - >-
    Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 <
    f71695e81f4cb428f3c7e2138eae88199005b52c
  - >-
    Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 <
    82f342b3b006ca1d65f4890c05f2ec32fcb808b6
  - >-
    Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 <
    50fb64defa72a3fecd0af1ca7c6b47b5c5c2b257
  - >-
    Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 <
    40ba329e8b4cd2fb11b0caf5e6a543ceaebb6009
  - >-
    Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 <
    b8dbe9648d69059cfe3a28917bfbf7e61efd7f15
  - Linux 3.4
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-06T15:26:02.982602Z'
published: '2026-05-01'
updated: '2026-11-06'
sourceUpdated: '2026-11-06T15:32:26.427Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-43020'
references:
  - url: 'https://git.kernel.org/stable/c/0f37d1e65c6d71ad94ccfb5c602163c525db789d'
  - url: 'https://git.kernel.org/stable/c/257cdb960d8ff6d60bb6461b03c814b6cf0c9e64'
  - url: 'https://git.kernel.org/stable/c/c34577f517b556fb6ca173d45bf7e766ae2564ce'
  - url: 'https://git.kernel.org/stable/c/f71695e81f4cb428f3c7e2138eae88199005b52c'
  - url: 'https://git.kernel.org/stable/c/82f342b3b006ca1d65f4890c05f2ec32fcb808b6'
  - url: 'https://git.kernel.org/stable/c/50fb64defa72a3fecd0af1ca7c6b47b5c5c2b257'
  - url: 'https://git.kernel.org/stable/c/40ba329e8b4cd2fb11b0caf5e6a543ceaebb6009'
  - url: 'https://git.kernel.org/stable/c/b8dbe9648d69059cfe3a28917bfbf7e61efd7f15'
tags:
  - cve.org
epss: 0.00129
epssPercentile: 0.02578
ingestedAt: '2026-11-06T15:54:04.035Z'
---

## Overview

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

Bluetooth: MGMT: validate LTK enc_size on load

Load Long Term Keys stores the user-provided enc_size and later uses
it to size fixed-size stack operations when replying to LE LTK
requests. An enc_size larger than the 16-byte key buffer can therefore
overflow the reply stack buffer.

Reject oversized enc_size values while validating the management LTK
record so invalid keys never reach the stored key state.

## Affected

- `Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 < 0f37d1e65c6d71ad94ccfb5c602163c525db789d`
- `Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 < 257cdb960d8ff6d60bb6461b03c814b6cf0c9e64`
- `Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 < c34577f517b556fb6ca173d45bf7e766ae2564ce`
- `Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 < f71695e81f4cb428f3c7e2138eae88199005b52c`
- `Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 < 82f342b3b006ca1d65f4890c05f2ec32fcb808b6`
- `Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 < 50fb64defa72a3fecd0af1ca7c6b47b5c5c2b257`
- `Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 < 40ba329e8b4cd2fb11b0caf5e6a543ceaebb6009`
- `Linux >= 346af67b8d116f01ef696fd47959a55deb2db8b6 < b8dbe9648d69059cfe3a28917bfbf7e61efd7f15`
- `Linux 3.4`

## Remediation

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