Elm27 FirmwareOperating system · Elmelectronics

CVE-2019-12797

CRITICAL · 9.8 CVSS v3.1 Published 2019-07-31
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable 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
A clone version of an ELM327 OBD2 Bluetooth device has a hardcoded PIN, leading to arbitrary commands to an OBD-II bus of a vehicle.

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

A clone/fake ELM327 OBD-II Bluetooth dongle contains a hardcoded PIN that cannot be changed, allowing any attacker within Bluetooth range to connect to the device and send arbitrary commands directly to the vehicle's OBD-II bus. This bus interfaces with critical vehicle systems including engine, transmission, and safety controls, enabling potential vehicle theft or manipulation of safety-critical functions.

MitigationReplace all clone ELM327 Bluetooth devices with genuine, reputable OBD-II diagnostic tools from trusted manufacturers that support proper authentication. For fleet operators, implement procurement policies requiring verified supply chains and consider network isolation for connected vehicle endpoints.

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
Elm27 FirmwareOperating system
Affected:all versions

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/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 ELM327 Bluetooth devices in use
    Check paired Bluetooth devices on any system that interfaces with vehicle OBD-II (laptops, tablets, dedicated scan tools). Look for Bluetooth devices with names containing 'ELM327', 'OBD', 'Vgate', 'Scanmaster', or similar OBD-II adapter names.
    Affected if Any Bluetooth-paired ELM327 or ELM327-compatible OBD-II adapter is present in the environment
  2. Inspect physical device branding
    Examine the actual OBD-II adapter hardware connected to the vehicle's diagnostic port. Look for: absence of Elm Electronics branding, generic 'ELM327' labeling without company logo, misspellings on the device, unusual physical quality or weight differences from expected hardware.
    Affected if The device shows signs of being a counterfeit or clone (no official Elm Electronics branding, generic packaging, or suspicious markings)
  3. Check if device PIN is changeable
    Access the device's Bluetooth configuration settings through companion mobile apps or AT commands. Attempt to navigate to security/PIN settings and verify if the PIN can be modified or if it remains fixed at a default value.
    Affected if The PIN cannot be changed and remains at a default value (such as 0000, 1234, or 000000)
  4. Verify firmware source
    If accessible via AT command interface, send 'ATI' command to query the firmware identification. Compare the reported manufacturer and firmware version against official Elm Electronics product documentation.
    Affected if Firmware reports as cloned, generic, or from a source other than Elm Electronics (e.g., common clone identifiers like 'V2.1' without proper Elm Electronics versioning)

If a Bluetooth OBD-II adapter is in use and it is a clone/fake ELM327 device with a hardcoded, unchangeable PIN, the environment is vulnerable to unauthorized Bluetooth connections and OBD-II bus manipulation.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Replace all clone ELM327 Bluetooth devices with genuine, reputable OBD-II diagnostic tools from trusted manufacturers that support proper authentication. For fleet operators, implement procurement policies requiring verified supply chains and consider network isolation for connected vehicle endpoints.

Fix this in Elm27 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing3.0 h
  • Review / QA2.0 h
17.0 hours of engineering $3,050
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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-2019-12797 in production — separate from our analysis above.

No notes yet

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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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