CVE-2021-35978
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 in Digi TransPort DR64, SR44 VC74, and WR. The ZING protocol allows arbitrary remote command execution with SUPER privileges. This allows an attacker (with knowledge of the protocol) to execute arbitrary code on the controller including overwriting firmware, adding/removing users, disabling the internal firewall, etc.
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 ZING protocol in Digi TransPort routers (DR64, SR44 VC74, WR) contains an authentication bypass allowing unauthenticated remote command execution with SUPER privileges. An attacker with protocol knowledge can execute arbitrary code, overwrite firmware, manipulate user accounts, and disable the internal firewall.
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, <= 8.3.1.2CVSS 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
- 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 checksWork through these to decide whether this CVE applies to you.
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Identify the Digi TransPort router modelLocate the model number on the physical device label or check the device inventory/management system. Common models are DR64, SR44, VC74, WR11, WR11 XT, WR21, WR31, or WR41.Affected if The device is one of these models: DR64, SR44, VC74, WR11, WR11 XT, WR21, WR31, or WR41.
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Check the installed firmware versionAccess the router web interface and navigate to the firmware or status page to view the current firmware version. Alternatively, log into the CLI and run 'show system' or 'ver' to display the firmware version.Affected if The firmware version falls within the affected ranges: DR64/VC74 <= 5.2.4.9; SR44 all versions; WR11/WR11 XT/WR21/WR31 <= 8.2.1.3; WR41: 5.0.0.0-5.2.4.6, 6.0.0.0-6.1.3.5, or 8.0.0.0-8.3.1.2.
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Determine if ZING protocol is enabledAccess the router web interface and check the ZING or protocol configuration settings. In CLI, look for ZING-related configuration using 'show running-config' or 'show config' and search for ZING entries.Affected if The ZING protocol is configured and enabled on the device.
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Verify ZING service exposureCheck network exposure by scanning for open ports associated with ZING (typically port 4000 or custom ports). Review firewall rules and access control lists to see if ZING is accessible from untrusted networks.Affected if The ZING service port is accessible from outside the trusted network or management segment.
The device is affected if it is a Digi TransPort model (DR64, SR44, VC74, WR11, WR11 XT, WR21, WR31, or WR41) running a firmware version within the affected ranges AND the ZING protocol is enabled and accessible.
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.
From vendor dataApply vendor firmware patches when available; until then, isolate affected devices behind firewalls or via network segmentation to limit external attack surface, and monitor for indicators of compromise.
- Consultation6.0 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-2021-35978 — 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-2021-35978 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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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.
- 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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