CVE-2021-37740

Name: CVE-2021-37740
Creator: NVD / NIST
Published: 2022-04-20T20:15:07.993+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 4.57%

Last modified Jun 17, 2026

CVE-2021-37740 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.. EPSS estimates a 4.57% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

4.57%

90.4th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Mdt	Scn-Ip000.03 Firmware	< 3.0.4
Mdt	Scn-Ip100.03 Firmware	< 3.0.4

References

https://github.com/robertguetzkow/CVE-2021-37740Exploit, Release Notes, Third Party Advisory
https://www.mdt.de/EN_IP_Interface_Router.htmlBroken Link
https://www.mdt.de/download/MDT_CL_SCN_IP_03_IP_Interface_Router.pdfRelease Notes, Vendor Advisory
https://github.com/robertguetzkow/CVE-2021-37740Exploit, Release Notes, Third Party Advisory
https://www.mdt.de/EN_IP_Interface_Router.htmlBroken Link
https://www.mdt.de/download/MDT_CL_SCN_IP_03_IP_Interface_Router.pdfRelease Notes, Vendor Advisory

Timeline

Published: Apr 20, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-37740?

How severe is CVE-2021-37740?

CVE-2021-37740 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 4.57% probability of exploitation in the next 30 days.

How do I fix CVE-2021-37740?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-37740?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST