Is CVE-2021-21962 actively exploited?

No active exploitation of CVE-2021-21962 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-21962 be exploited remotely?

Yes. CVE-2021-21962 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-21962?

CVE-2021-21962 has a CVSS score of 8.1 (HIGH).

HOME VULNERABILITIESCVE-2021-21962

HIGH

CVE-2021-21962

CWE-122Published: February 4, 2022· Updated: Jun 17, 2026

8.1

CVSS v3.1

Official Description

A heap-based buffer overflow vulnerability exists in the OTA Update u-download functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A series of specially-crafted MQTT payloads can lead to remote code execution. An attacker must perform a man-in-the-middle attack in order to trigger this vulnerability.

NVD Source

Technical Analysis

CVE-2021-21962 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 8.1.