CVE-2021-37188
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 · uneditedAn issue was discovered on Digi TransPort devices through 2021-07-21. An authenticated attacker may load customized firmware (because the bootloader does not verify that it is authentic), changing the behavior of the gateway.
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 confidenceThe Digi TransPort devices contain a bootloader that does not verify the cryptographic signature or authenticity of firmware before loading it. An authenticated attacker can exploit this by loading customized (malicious) firmware to alter the gateway's behavior.
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<= 5.2.4.9all versions<= 5.2.4.9<= 8.2.1.3<= 8.2.1.3<= 8.2.1.3<= 8.2.1.3>= 5.0.0.0, <= 5.2.4.6>= 6.0.0.0, <= 6.1.3.5>= 8.0.0.0, <= 8.3.1.2<= 8.3.1.2CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify the Digi TransPort device modelAccess the device's web interface, CLI, or physical label to determine the exact model (Dr64, Vc74, Wr11, Wr11 Xt, Wr21, Wr31, Wr41, or Wr44)Affected if The device is not one of these models - the CVE does not apply
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Check the installed firmware versionAccess the device's web interface under 'Status' or 'System Information', or use the CLI command 'show system information' or 'version' to retrieve the firmware versionAffected if The firmware version falls within the affected ranges: Dr64/Vc74 <= 5.2.4.9; Wr11/Wr11 Xt/Wr21/Wr31 <= 8.2.1.3; Wr41 >= 5.0.0.0 to <= 5.2.4.6, >= 6.0.0.0 to <= 6.1.3.5, or >= 8.0.0.0 to <= 8.3.1.2; Wr44 <= 8.3.1.2
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Verify whether secure boot is enabled in the bootloaderAccess the device's boot menu or bootloader configuration (often via serial console during boot, or via 'show boot config' / 'show secure boot status' CLI commands). Look for settings related to 'secure boot', 'signature verification', 'firmware authentication', or 'boot security'Affected if Secure boot or firmware signature verification is disabled or not configured - the vulnerability is present and exploitable if an attacker gains authenticated access
The device is affected if it is a Digi TransPort model (Dr64, Vc74, Wr11, Wr11 Xt, Wr21, Wr31, Wr41, or Wr44) with a firmware version within the specified vulnerable ranges AND secure boot with cryptographic signature verification is not enabled in the bootloader.
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 · scopedEnable secure boot with cryptographic signature verification in the bootloader and ensure only signed firmware can be executed. Update to firmware versions that implement proper firmware authenticity checks.
Latest firmware version available from Digi for each specific TransPort model (firmware releases after the affected version ranges: >5.2.4.9 for Dr64/Vc74, >8.2.1.3 for Wr11/Wr11 Xt/Wr21/Wr31, >8.3.1.2 for Wr44, and >5.2.4.6/6.1.3.5/8.3.1.2 for Wr41 depending on the branch)
- 1. Identify the exact Digi TransPort device model from the affected product list (Dr64, Vc74, Wr11, Wr11 Xt, Wr21, Wr31, Wr41, or Wr44)
- 2. Check the current firmware version installed on the device through the device's web interface or CLI
- 3. Visit the official Digi support website (www.digi.com) and navigate to the firmware download section for your specific device model
- 4. Download the latest available firmware version for your device model
- 5. Review the firmware release notes to confirm the update addresses CVE-2021-37188 (bootloader firmware authenticity verification)
- 6. Backup the current device configuration before performing the firmware upgrade
- 7. Upload and install the new firmware following Digi's standard firmware upgrade procedure via web interface or CLI
- 8. After upgrade, verify the device is functioning correctly and the new firmware version is installed
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation10.0 h
- Implementation50.0 h
- Testing24.0 h
- Review / QA12.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-37188 — 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-2021-37188 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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- 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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