Is CVE-2021-21969 actively exploited?

No active exploitation of CVE-2021-21969 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-21969 be exploited remotely?

Yes. CVE-2021-21969 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-21969?

CVE-2021-21969 has a CVSS score of 8.1 (HIGH).

HOME VULNERABILITIESCVE-2021-21969

HIGH

CVE-2021-21969

CWE-120Published: February 4, 2022· Updated: Jun 17, 2026

8.1

CVSS v3.1

Official Description

An out-of-bounds write vulnerability exists in the HandleSeaCloudMessage functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. The HandleIncomingSeaCloudMessage function uses at [4] the json_object_get_string to populate the p_payload global variable. The p_payload is only 0x100 bytes long, and the total MQTT message could be up to 0x201 bytes. Because the function json_object_get_string will fill str based on the length of the json’s value and not the actual str size, this would result in a possible out-of-bounds write.

NVD Source

Technical Analysis

CVE-2021-21969 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.