How severe is CVE-2021-37740?

CVE-2021-37740 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-37740 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-37740?

CVE-2021-37740 primarily affects Mdt Scn-ip000.03 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-37740?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-37740 published?

CVE-2021-37740 was published on 2022-04-20 and last updated on 2026-06-17.

CVE-2021-37740

CVE-2021-37740 is a high-severity vulnerability in Mdt Scn-ip000.03 Firmware with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 7.8
EPSS exploit prediction: 5% (90th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Mdt Scn-ip000.03 Firmware
Published: 2022-04-20
Last modified: 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.

Frequently asked questions

What is CVE-2021-37740?: 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.
How severe is CVE-2021-37740?: CVE-2021-37740 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-37740 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-37740?: CVE-2021-37740 primarily affects Mdt Scn-ip000.03 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-37740?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-37740 published?: CVE-2021-37740 was published on 2022-04-20 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:o:mdt:scn-ip000.03_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:mdt:scn-ip100.03_firmware:*:*:*:*:*:*:*:*