CVE-2020-26556

Authentication bypass via malleable commitment

Published May 24, 2021 · Updated Aug 4, 2024

Authentication bypass in Bluetooth Mesh Profile 1.0 and 1.0.1 allows nearby attackers to complete provisioning and obtain a NetKey via malleable commitment. The provisioning authentication protocol accepts a commitment that can be manipulated while an attacker brute-forces the AuthValue before timeout. The attack requires wireless proximity and substantial computation; a recovered NetKey permits network-layer decryption and message relay but not application-data decryption.

CVSS severity7.5
High
EPSS probability0.91%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in Bluetooth Mesh Profile 1.0 and 1.0.1 allows nearby attackers to complete provisioning and obtain a NetKey via malleable commitment. The provisioning authentication protocol accepts a commitment that can be manipulated while an attacker brute-forces the AuthValue before timeout. The attack requires wireless proximity and substantial computation; a recovered NetKey permits network-layer decryption and message relay but not application-data decryption.

The record

CVE
CVE-2020-26556
Published
May 24, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-307, T1110
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

2.9NVDAV:A/AC:M/Au:N/C:P/I:N/A:N
7.5NVDCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:H/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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-307Improper Restriction of Excessive Authentication Attempts
T1110Brute Force

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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