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Mesh ProfileApplication · Bluetooth

CVE-2020-26559

HIGH · 8.8 CVSS v3.1 Published 2021-05-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
93/100
Remediation priority · Urgent
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Bluetooth Mesh Provisioning in the Bluetooth Mesh profile 1.0 and 1.0.1 may permit a nearby device (participating in the provisioning protocol) to identify the AuthValue used given the Provisioner’s public key, and the confirmation number and nonce provided by the provisioning device. This could permit a device without the AuthValue to complete provisioning without brute-forcing the AuthValue.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

The Bluetooth Mesh provisioning protocol in versions 1.0 and 1.0.1 contains a cryptographic weakness that allows an attacker to derive the AuthValue secret from publicly transmitted values (Provisioner public key, confirmation number, and nonce) during the provisioning handshake. This bypasses the intended brute-force protection of the AuthValue mechanism, enabling unauthorized device provisioning.

MitigationUpdate Bluetooth Mesh stack implementations to versions that incorporate corrected cryptographic handling in the provisioning protocol; ensure provisioning occurs in secure environments to reduce proximity attack vectors.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Mesh ProfileApplication
Affected:= 1.0.0= 1.0.1

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Bluetooth Mesh usage
    Check system processes, services, or application dependencies for Bluetooth Mesh stack implementations (e.g., libraries like BlueZ, vendor SDKs). Look for mesh provisioning daemons, mesh-related processes, or applications that advertise Bluetooth Mesh capabilities.
    Affected if Bluetooth Mesh Profile functionality is present in the environment
  2. Determine Bluetooth Mesh stack version
    Query the installed Bluetooth Mesh stack or library version using vendor-specific commands, package managers, or application version reporting. For BlueZ, check 'bluetoothctl version' or inspect installed package versions. For vendor SDKs, consult their API or configuration files.
    Affected if The installed version equals exactly 1.0.0 or 1.0.1
  3. Verify provisioning protocol is in use
    Inspect active Bluetooth connections and logging for mesh provisioning operations. Check if the device is acting as a Provisioner (initiating provisioning) or as a Provisionee (being provisioned). Monitor for provisioning handshake traffic.
    Affected if The system is actively performing or has recently performed Bluetooth Mesh provisioning using the affected software
  4. Confirm AuthValue derivation exposure
    Review public values exchanged during provisioning: Provisioner public key, confirmation number, and nonce. In a compromised scenario, an attacker with proximity could capture these and derive the AuthValue. There is no direct file to inspect for this in a defensive check.
    Affected if Provisioning has occurred with an affected version and the environment is network-accessible to potential attackers

A user is affected if their Bluetooth Mesh stack version is exactly 1.0.0 or 1.0.1 and they have performed or will perform provisioning operations using that vulnerable implementation.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update Bluetooth Mesh stack implementations to versions that incorporate corrected cryptographic handling in the provisioning protocol; ensure provisioning occurs in secure environments to reduce proximity attack vectors.

Recommended fix Moderate confidence

Bluetooth Mesh Profile 1.1 or later (consult vendor-specific updates)

  1. Upgrade the Bluetooth Mesh implementation to a version that implements the fixes for CVE-2020-26559. This vulnerability in the Bluetooth Mesh Provisioning protocol (versions 1.0 and 1.0.1) allows identification of the AuthValue without brute-forcing, enabling unauthorized device provisioning.
  2. Consult the Bluetooth SIG and your device/firmware vendor for the specific updated mesh stack or profile version that addresses this vulnerability.
  3. After upgrading, verify that provisioning now requires proper AuthValue and cannot be completed by nearby devices with only the public key, confirmation number, and nonce.
  4. Test the provisioning flow in a controlled environment to confirm the vulnerability is remediated before deploying to production.
Caveat Review vendor release notes for any changes to provisioning behavior or compatibility with older devices

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Mesh Profile Scoped from the published advisory
  • Consultation6.0 h
  • Implementation16.0 h
  • Testing8.0 h
  • Review / QA4.0 h
34.0 hours of engineering $6,000
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-26559 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
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  • Version or environment caveats, and links to real fixes
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