Is CVE-2021-21963 actively exploited?

No active exploitation of CVE-2021-21963 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2021-21963 be exploited remotely?

Yes. CVE-2021-21963 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2021-21963?

CVE-2021-21963 has a CVSS score of 5.9 (MEDIUM).

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MEDIUM

CVE-2021-21963

CWE-311Published: February 4, 2022· Updated: Jun 17, 2026

5.9

CVSS v3.1

Official Description

An information disclosure vulnerability exists in the Web Server functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A specially-crafted man-in-the-middle attack can lead to a disclosure of sensitive information. An attacker can perform a man-in-the-middle attack to trigger this vulnerability.

NVD Source

Technical Analysis

CVE-2021-21963 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), with a CVSS base score of 5.9.