CVE-2021-41545
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 · uneditedA vulnerability has been identified in Desigo DXR2 (All versions < V01.21.142.5-22), Desigo PXC3 (All versions < V01.21.142.4-18), Desigo PXC4 (All versions < V02.20.142.10-10884), Desigo PXC5 (All versions < V02.20.142.10-10884). When the controller receives a specific BACnet protocol packet, an exception causes the BACnet communication function to go into a “out of work” state and could result in the controller going into a “factory reset” state.
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 confidenceA vulnerability in Siemens Desigo DXR2, PXC3, PXC4, and PXC5 controllers allows a specially crafted BACnet protocol packet to trigger an exception that puts the BACnet communication function into an 'out of work' state, potentially causing the controller to factory reset.
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< 01.21.142.5-22< 01.21.142.4-18< 02.20.142.10-10884< 02.20.142.10-10884CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify the controller modelAccess the controller via its web interface, Desigo Engineering tool, or check the physical device label to determine if the model is DXR2, PXC3, PXC4, or PXC5Affected if The model is one of these four Desigo controllers
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Determine the installed firmware versionVia the controller web interface under System Information or Hardware Info, or using the Desigo Engineering tool to read the firmware version propertyAffected if The firmware version is below 01.21.142.5-22 for DXR2, below 01.21.142.4-18 for PXC3, or below 02.20.142.10-10884 for PXC4/PXC5
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Confirm BACnet communication is enabledCheck the controller configuration via the web interface or Desigo Engineering tool for active BACnet stack or BACnet/IP settingsAffected if BACnet protocol communication is enabled and the controller participates in a BACnet network
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Inspect BACnet communication statusMonitor the BACnet communication status via the controller web interface, Desigo Engineering tool, or external BACnet diagnostic tool for 'out of work' or exception error statesAffected if BACnet communication shows repeated exceptions, is in an 'out of work' state, or has triggered unexpected resets
A user is affected if they have a DXR2, PXC3, PXC4, or PXC5 controller running firmware below the specified version thresholds and BACnet communication is enabled, with observable BACnet communication failures or resets.
Generated from the published advisory. Verify against your own configuration.
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 · scoped01.21.142.4-1801.21.142.5-2202.20.142.10-10884
Apply the vendor-provided firmware update (V01.21.142.5-22 for DXR2, V01.21.142.4-18 for PXC3, V02.20.142.10-10884 for PXC4/PXC5) after scheduling a maintenance window and backing up controller configurations.
Desigo DXR2: V01.21.142.5-22 | Desigo PXC3: V01.21.142.4-18 | Desigo PXC4: V02.20.142.10-10884 | Desigo PXC5: V02.20.142.10-10884
- Identify the specific Desigo controller model (DXR2, PXC3, PXC4, or PXC5) in your environment
- Access the controller's web interface or management console
- Navigate to the firmware update section
- Obtain the appropriate firmware file from Siemens support (cert-portal.siemens.com)
- For DXR2: Download firmware version 01.21.142.5-22 or higher
- For PXC3: Download firmware version 01.21.142.4-18 or higher
- For PXC4: Download firmware version 02.20.142.10-10884 or higher
- For PXC5: Download firmware version 02.20.142.10-10884 or higher
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-41545 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-41545 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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