Miniserver Gen 1 FirmwareOperating system · Loxone

CVE-2020-27488

CRITICAL · 9.8 CVSS v3.1 Published 2021-01-13
Fix available
A fix is available. Upgrade to 11.1.9.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit 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
Loxone Miniserver devices with firmware before 11.1 (aka 11.1.9.3) are unable to use an authentication method that is based on the "signature of the update package." Therefore, these devices (or attackers who are spoofing these devices) can continue to use an unauthenticated cloud service for an indeterminate time period (possibly forever). Once an individual device's firmware is updated, and authentication occurs once, the cloud service recategorizes the device so that authentication is subsequently always required, and spoofing cannot occur.

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
How this class of weakness works · CWE-287

The mechanism that verifies who a user is can be side-stepped or fooled, letting an attacker act as someone they're not. Everything built on top of that identity then becomes untrustworthy. Fixing it means hardening the full authentication flow, including edge cases, tokens, and secondary paths.

General guidance for the improper authentication class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
Miniserver Gen 1 FirmwareOperating system
Affected:< 11.1.9.3

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

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
Upgrade available Upgrade to 11.1.9.3 or later
Fixed in 11.1.9.3
Recommended fix High confidence

Miniserver Gen 1 Firmware 11.1.9.3 or later (11.1.x)

  1. 1. Access the Loxone Miniserver web interface or Loxone Config software
  2. 2. Navigate to the firmware update section (typically under 'Hardware' > 'Miniserver' > 'Firmware')
  3. 3. Check the current firmware version to confirm it is below 11.1.9.3
  4. 4. Initiate a firmware update to version 11.1.9.3 or later
  5. 5. Wait for the update process to complete and the device to reboot
  6. 6. After reboot, verify the new firmware version is 11.1.9.3 or higher
  7. 7. Ensure the Miniserver connects to the Loxone cloud service at least once after the update to trigger the authentication recategorization

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

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $2,300. Get the upgrade done

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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-2020-27488 in production — separate from our analysis above.

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  • Version or environment caveats, and links to real fixes
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