CVE-2026-43020

Kernel memory corruption via oversized Bluetooth LTK

Published May 1, 2026 · Updated May 1, 2026

Stack buffer overflow in the Linux kernel Bluetooth MGMT subsystem allows local users to corrupt kernel memory via a loaded LTK. The Load Long Term Keys path stores an unchecked enc_size and later uses it for fixed-size stack operations when replying to LE LTK requests, so values above the 16-byte key buffer overwrite the reply stack buffer. Exploitation requires CAP_NET_ADMIN in the initial user namespace, equivalent to root-level privileges on Ubuntu; corruption can crash the kernel or alter kernel memory.

CVSS severity7.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack buffer overflow in the Linux kernel Bluetooth MGMT subsystem allows local users to corrupt kernel memory via a loaded LTK. The Load Long Term Keys path stores an unchecked enc_size and later uses it for fixed-size stack operations when replying to LE LTK requests, so values above the 16-byte key buffer overwrite the reply stack buffer. Exploitation requires CAP_NET_ADMIN in the initial user namespace, equivalent to root-level privileges on Ubuntu; corruption can crash the kernel or alter kernel memory.

The record

CVE
CVE-2026-43020
Published
May 1, 2026
Updated
May 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-787
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=3.4
  2. Affected versionversion=346af67b8d116f01ef696fd47959a55deb2db8b6 <0f37d1e65c6d71ad94ccfb5c602163c525db789d
  3. Affected versionversion=346af67b8d116f01ef696fd47959a55deb2db8b6 <257cdb960d8ff6d60bb6461b03c814b6cf0c9e64
  4. Affected versionversion=346af67b8d116f01ef696fd47959a55deb2db8b6 <40ba329e8b4cd2fb11b0caf5e6a543ceaebb6009
  5. Affected versionversion=346af67b8d116f01ef696fd47959a55deb2db8b6 <50fb64defa72a3fecd0af1ca7c6b47b5c5c2b257
  6. Affected versionversion=346af67b8d116f01ef696fd47959a55deb2db8b6 <82f342b3b006ca1d65f4890c05f2ec32fcb808b6
  7. Affected versionversion=346af67b8d116f01ef696fd47959a55deb2db8b6 <b8dbe9648d69059cfe3a28917bfbf7e61efd7f15
  8. Affected versionversion=346af67b8d116f01ef696fd47959a55deb2db8b6 <c34577f517b556fb6ca173d45bf7e766ae2564ce
  9. Affected versionversion=346af67b8d116f01ef696fd47959a55deb2db8b6 <f71695e81f4cb428f3c7e2138eae88199005b52c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.4; version=346af67b8d116f01ef696fd47959a55deb2db8b6 <0f37d1e65c6d71ad94ccfb5c602163c525db789d; version=346af67b8d116f01ef696fd47959a55deb2db8b6 <257cdb960d8ff6d60bb6461b03c814b6cf0c9e64; version=346af67b8d116f01ef696fd47959a55deb2db8b6 <40ba329e8b4cd2fb11b0caf5e6a543ceaebb6009; version=346af67b8d116f01ef696fd47959a55deb2db8b6 <50fb64defa72a3fecd0af1ca7c6b47b5c5c2b257; version=346af67b8d116f01ef696fd47959a55deb2db8b6 <82f342b3b006ca1d65f4890c05f2ec32fcb808b6; version=346af67b8d116f01ef696fd47959a55deb2db8b6 <b8dbe9648d69059cfe3a28917bfbf7e61efd7f15; version=346af67b8d116f01ef696fd47959a55deb2db8b6 <c34577f517b556fb6ca173d45bf7e766ae2564ce; version=346af67b8d116f01ef696fd47959a55deb2db8b6 <f71695e81f4cb428f3c7e2138eae88199005b52c

Published CVSS scores

7.8Canonical UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.3Oracle LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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