CVE-2020-26555

Unauthorized pairing via reflected encrypted nonce

Published May 24, 2021 · Updated Nov 4, 2025

Authentication bypass in Bluetooth Core Specification 1.0B through 5.2 allows physically proximate attackers to pair without the PIN. The BR/EDR legacy PIN-pairing procedure accepts a peer that spoofs the victim's BD_ADDR and reflects the encrypted nonce, producing a known link key. The target must be within wireless range, connectable, bondable, and generally discoverable; successful pairing permits encrypted access to profiles allowed for bonded devices.

CVSS severity5.4
Medium
EPSS probability0.88%
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 Core Specification 1.0B through 5.2 allows physically proximate attackers to pair without the PIN. The BR/EDR legacy PIN-pairing procedure accepts a peer that spoofs the victim's BD_ADDR and reflects the encrypted nonce, producing a known link key. The target must be within wireless range, connectable, bondable, and generally discoverable; successful pairing permits encrypted access to profiles allowed for bonded devices.

The record

CVE
CVE-2020-26555
Published
May 24, 2021
Updated
Nov 4, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-863
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 24, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 4, 2025Record 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

4.8NIST NVDAV:A/AC:L/Au:N/C:P/I:P/A:N
5.4NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

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-863Incorrect Authorization

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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