CVE-2021-37740

HIGH

MDT SCN-IP000.03 and SCN-IP100.03 Firmware < 3.0.4 - Denial of Service via Modified SESSION_REQUEST Frame

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-37740. PoCs published by robertguetzkow.

AI-analyzed exploit summary This repository contains a functional proof-of-concept exploit for CVE-2021-37740, a denial-of-service vulnerability in MDT KNXnet/IP Secure devices. The exploit sends a malformed SESSION_REQUEST frame with an invalid total length field, causing the device to become unresponsive.

Description

A denial of service vulnerability exists in MDT's firmware for the KNXnet/IP Secure router SCN-IP100.03 and KNX IP interface SCN-IP000.03 before v3.0.4, that allows a remote attacker to turn the device unresponsive to all requests on the KNXnet/IP Secure layer, until the device is rebooted, via a SESSION_REQUEST frame with a modified total length field.

Exploits (1)

nomisec WORKING POC 6 stars
by robertguetzkow · poc
https://github.com/robertguetzkow/CVE-2021-37740

This repository contains a functional proof-of-concept exploit for CVE-2021-37740, a denial-of-service vulnerability in MDT KNXnet/IP Secure devices. The exploit sends a malformed SESSION_REQUEST frame with an invalid total length field, causing the device to become unresponsive.

Classification
Working Poc 100%
Attack Type
Dos
Complexity
Trivial
Reliability
Reliable
Target: MDT KNXnet/IP Secure router SCN-IP100.03 and interface SCN-IP000.03 (firmware v3.0.3)
No auth needed
Prerequisites: Network access to the target device · TCP port 3671 accessible
devstral-2 · analyzed Feb 18, 2026 Full analysis →

References (3)

Core 3
Core References
Broken Link x_refsource_misc
https://www.mdt.de/EN_IP_Interface_Router.html
Release Notes, Vendor Advisory x_refsource_misc
https://www.mdt.de/download/MDT_CL_SCN_IP_03_IP_Interface_Router.pdf
Exploit, Release Notes, Third Party Advisory x_refsource_misc
https://github.com/robertguetzkow/CVE-2021-37740

Scores

CVSS v3 7.5
EPSS 0.0457
EPSS Percentile 90.4%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

Status published
Products (2)
mdt/scn-ip000.03_firmware < 3.0.4
mdt/scn-ip100.03_firmware < 3.0.4
Published Apr 20, 2022
Tracked Since Feb 18, 2026