CVE-2021-33526

MB connect line mbDIALUP — vulnerability CVE-2021-33526

In 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.

CVSS 7.8Patch available

This record: live connection— last retrieved: 7 November 2026 at 04:38.

Vendors

MB connect line, Helmholz

Products

mbDIALUP, shDialup

up to version <=3.9R0.0

Published

2 August 2021

Last modified

17 June 2026

Original source information

Taken directly from NVD, CISA or the vendor — sometimes in English, unchanged from the source.

Technical description

CVSS 3.1 — vector details

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack vector

LOCAL

Privileges required

LOW

User interaction

NONE

Confidentiality

High

Integrity

High

Availability

High

EPSS — Exploit Prediction Scoring System

Probability of exploitation within 30 days

0.3%

Percentile

17e

Source: FIRST.org, updated on 6 November 2026.

Patch information

Update to 3.9R0.5

IACS Radar assessment

Our own interpretation and context for the source data above.

IACS Radar assessment

Our own interpretation and context for this vulnerability — not an official source.

IACS Radar priority score

41/ 100

Based on CVSS 7.8, EPSS 0.3%, industrial relevance 40/100.

Combines CVSS, EPSS, KEV status, industrial relevance and exposure relevance — a complement to, not a replacement for, the individual scores below and above.

Conditions for exploitation

•Local or adjacent access to the device is required.
•Limited user privileges are required.
•No user interaction required.

Operational impact & energy relevance

Possible loss of visibility of or control over the process upon successful exploitation.

No strong energy-sector-specific signals recognised; general OT/ICS relevance.

Recommended defensive measures

•Limit user rights to what is strictly necessary through role-based access.
•Restrict network access to the affected device to a dedicated OT management segment.
•Implement network segmentation in line with zones and conduits (IEC 62443-3-2).
•Monitor for abnormal protocol traffic using an OT-aware detection system.

Industrial relevance score

40/ 100

• Mentioned in an official CISA ICS advisory, which confirms direct relevance to industrial control systems.

Classification is provisional; manual verification by an OT security analyst is recommended.

Classified by IACS Radar-analysepijplijn (geautomatiseerd) on 7 November 2026.

IEC 62443 mapping

IEC 62443-4-2FR2 · Gebruiksbeheer

Automatic IACS Radar assessment based on the reported CWE weakness classification; not an official certification statement.

Loading vulnerabilities…