CVE-2021-33526
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 MB connect line mbDIALUP versions <= 3.9R0.0 a low privileged local attacker can send a command to the service running with NT AUTHORITY\SYSTEM instructing it to execute a malicous OpenVPN configuration resulting in arbitrary code execution with the privileges of the service.
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 local privilege escalation vulnerability in mbDIALUP allows a low-privileged local attacker to send commands to a service running as NT AUTHORITY\SYSTEM, instructing it to execute a malicious OpenVPN configuration, resulting in arbitrary code execution with SYSTEM privileges.
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<= 3.9r0.0CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/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 if mbDIALUP is installedCheck for the presence of the mbDIALUP service or executable on the system. Look for a service named 'mbDIALUP' or directories containing 'mbDIALUP' or 'mbconnectline' in Program Files or Program Files (x86).Affected if The mbDIALUP software from Mbconnectline is found on the system
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Determine installed mbDIALUP versionLocate the mbDIALUP executable (commonly in C:\Program Files\mbconnectline\mbDIALUP\ or similar path) and check its version properties, or query the installed version through the software inventory if available.Affected if The installed version is 3.9r0.0 or lower
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Verify if mbDIALUP service runs as SYSTEMOpen Windows Services (services.msc), find the mbDIALUP service, right-click and select Properties, and check the 'Log on as' account. Alternatively, run 'sc query mbDIALUP' and 'sc qc mbDIALUP' to check service configuration.Affected if The service is configured to run as NT AUTHORITY\SYSTEM or LocalSystem account
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Check for OpenVPN configuration interactionExamine the mbDIALUP configuration directory for OpenVPN-related config files (typically .ovpn or config.ovpn files) and review any OpenVPN-related settings or logs within the mbDIALUP application data folders.Affected if OpenVPN configuration files are present and configurable by low-privileged users, or the service loads OpenVPN configurations from user-accessible locations
A system is affected if mbDIALUP version 3.9r0.0 or lower is installed and the mbDIALUP service runs with SYSTEM privileges while handling OpenVPN configurations accessible to low-privileged users.
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 dataUpdate mbDIALUP to a version beyond 3.9R0.0 when available. Until then, restrict local access to the system to trusted, privileged users only and monitor for suspicious commands to the service.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-33526 — 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-2021-33526 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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