6873i Sip FirmwareOperating system · Mitel

CVE-2020-27639

HIGH · 8.1 CVSS v3.1 Published 2020-12-18
Fix available
A fix is available. Upgrade to 5.1.0 or later.
See remediation →
86/100
Remediation priority · High
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
The Bluetooth handset of Mitel MiVoice 6873i, 6930, and 6940 SIP phones with firmware before 5.1.0.SP6 could allow an unauthenticated attacker within Bluetooth range to pair a rogue Bluetooth device when a phone handset loses connection, due to an improper pairing mechanism. A successful exploit could allow an attacker to eavesdrop on conversations.

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 · high confidence

The Mitel MiVoice 6873i, 6930, and 6940 SIP phones have an improper Bluetooth pairing mechanism in the handset firmware prior to 5.1.0.SP6. When the phone handset loses connection, an unauthenticated attacker within Bluetooth range can exploit the flawed pairing process to connect a rogue Bluetooth device, enabling eavesdropping on audio conversations.

MitigationUpgrade Mitel MiVoice 6873i, 6930, and 6940 SIP phone firmware to version 5.1.0.SP6 or later to remediate the improper Bluetooth pairing vulnerability.

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
6873i Sip FirmwareOperating system
Affected:< 5.1.0= 5.1.0
6930 Sip FirmwareOperating system
Affected:< 5.1.0= 5.1.0
6940 Sip FirmwareOperating system
Affected:< 5.1.0= 5.1.0

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
None
Availability
High

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/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 the phone model
    Access the phone's web interface (http://<phone_ip>) or check the physical device label to confirm the model is one of: 6873i, 6930, or 6940
    Affected if The device is a Mitel 6873i, 6930, or 6940 SIP phone
  2. Check the installed firmware version
    Log into the phone's web administrative interface and navigate to Status or System Information page to view the firmware version; alternatively, access the device directly and check the firmware information in the settings
    Affected if The firmware version is < 5.1.0 or exactly 5.1.0
  3. Verify if Bluetooth is enabled
    Access the phone's web interface and check the Bluetooth settings page (under Hardware or Peripheral settings) to determine if Bluetooth functionality is turned on
    Affected if Bluetooth is enabled on the device
  4. Confirm Bluetooth handset pairing capability
    Check the phone's settings to verify that Bluetooth handset or headset pairing is configured or available; the vulnerability exploits the pairing process when the handset loses connection
    Affected if Bluetooth handset/headset pairing is available or configured

The device is affected if it is a Mitel 6873i, 6930, or 6940 SIP phone with firmware version 5.1.0 or lower, and Bluetooth is enabled with handset pairing functionality available.

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.

From vendor data
Upgrade available Upgrade to 5.1.0 or later
Fixed in 5.1.0
Interim mitigation

Upgrade Mitel MiVoice 6873i, 6930, and 6940 SIP phone firmware to version 5.1.0.SP6 or later to remediate the improper Bluetooth pairing vulnerability.

Fix this in 6873i Sip Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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Scan for this in your stack

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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-2020-27639 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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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