RealportApplication · Digi
CVE-2021-36767
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 · uneditedIn Digi RealPort through 4.10.490, authentication relies on a challenge-response mechanism that gives access to the server password, making the protection ineffective. An attacker may send an unauthenticated request to the server. The server will reply with a weakly-hashed version of the server's access password. The attacker may then crack this hash offline in order to successfully login to the server.
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 confidenceDigi RealPort through version 4.10.490 contains a pre-authentication vulnerability where the challenge-response authentication mechanism exposes a weakly-hashed version of the server password in response to unauthenticated requests. An attacker can intercept this hash and crack it offline to gain legitimate access to the server.
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
RealportApplication
<= 1.9-40<= 4.10.490all versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS 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 Digi RealPort presenceLocate Digi RealPort software on the system or identify Digi hardware devices (Connectport TS 8/16, Connectport LTS 8/16/32, Passport Integrated Console Server, CM, Portserver TS, Portserver TS Mei, Portserver TS Mei Hardened) on the networkAffected if Digi RealPort software or any listed device is present and accessible on the network
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Determine RealPort software versionCheck the installed version of Digi RealPort software by examining the application version through the software management interface or the program's version informationAffected if The installed version is 1.9-40 or lower, or 4.10.490 or lower
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Check device firmware versionFor hardware devices (Connectport, Portserver, CM series), access the device management interface and check the firmware versionAffected if The device firmware is any version (all versions are listed as affected for these models)
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Verify network exposure of authentication serviceDetermine if the RealPort service port is accessible from network sources. This is a pre-authentication flaw, meaning the vulnerability is exposed to unauthenticated network requestsAffected if The RealPort service port is exposed to untrusted network segments without firewall or access controls
A user is affected if Digi RealPort software version is at or below 1.9-40 or at or below 4.10.490, or if any listed Digi hardware device with any firmware version has its RealPort service accessible on the network.
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 dataUpgrade to the latest version of Digi RealPort (4.10.490 or later). If no patch is available, restrict network access to the RealPort service using firewalls or network segmentation, and consider disabling the service if not required.
Fix this in Realport
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-36767 — 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-2021-36767 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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