Is CVE-2021-20999 actively exploited?

No active exploitation of CVE-2021-20999 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-20999 be exploited remotely?

Yes. CVE-2021-20999 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-20999?

CVE-2021-20999 has a CVSS score of 9.8 (CRITICAL).

HOME VULNERABILITIESCVE-2021-20999

CRITICAL

CVE-2021-20999

CWE-668Published: May 13, 2021· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

In Weidmüller u-controls and IoT-Gateways in versions up to 1.12.1 a network port intended only for device-internal usage is accidentally accessible via external network interfaces. By exploiting this vulnerability the device may be manipulated or the operation may be stopped.

NVD Source

Technical Analysis

CVE-2021-20999 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.