What’s Vulnerable › Vulnerabilities

CVE-2021-37740

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-04-20 · updated 2026-06-17

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.

Affected products

• Mdt Scn-Ip000.03 Firmware: before 3.0.4 — fixed in 3.0.4
• Mdt Scn-Ip100.03 Firmware: before 3.0.4 — fixed in 3.0.4

How to fix

Upgrade to a fixed version: Mdt Scn-Ip000.03 Firmware 3.0.4; Mdt Scn-Ip100.03 Firmware 3.0.4. Check the vendor advisory for mitigations.

References

• https://github.com/robertguetzkow/CVE-2021-37740
• https://www.mdt.de/EN_IP_Interface_Router.html
• https://www.mdt.de/download/MDT_CL_SCN_IP_03_IP_Interface_Router.pdf
• https://github.com/robertguetzkow/CVE-2021-37740
• https://www.mdt.de/EN_IP_Interface_Router.html
• https://www.mdt.de/download/MDT_CL_SCN_IP_03_IP_Interface_Router.pdf

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