Is CVE-2021-40390 actively exploited?

No active exploitation of CVE-2021-40390 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-40390 be exploited remotely?

Yes. CVE-2021-40390 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-40390?

CVE-2021-40390 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2021-40390

CWE-798Published: April 14, 2022· Updated: Jun 17, 2026

9.8

CVSS v3.1

Official Description

An authentication bypass vulnerability exists in the Web Application functionality of Moxa MXView Series 3.2.4. A specially-crafted HTTP request can lead to unauthorized access. An attacker can send an HTTP request to trigger this vulnerability.

NVD Source

Technical Analysis

CVE-2021-40390 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.