CVE-2021-21965: A denial of service vulnerability exists in the SeaMax remote configuration functionality of Sealevel Systems,

This week

CRITICAL 9.3REMOTEMITIGATE

CVE-2021-21965 is a critical-severity flaw (CVSS 9.3) affecting seaconnect 370w firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A denial of service vulnerability exists in the SeaMax remote configuration functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. Specially-crafted network packets can lead to denial of service. An attacker can send a malicious packet to trigger this vulnerability.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.3 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 37%)
CISA exploited list	No
Weakness	CWE-284, CWE-287
Published	2022-02-04
Last modified	2026-06-17

Publisher (CNA): Talos · Vendor: sealevel

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2022-02-04 23:15 UTCPublished CVE record published
2026-06-17 03:36 UTCUpdated Record last modified

sealevel seaconnect 370w firmware MITIGATE

Affected: 1.3.34

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.3.34

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-21965?

seaconnect 370w firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-21965 being exploited?

CVE-2021-21965 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-21965 affect?

CVE-2021-21965 affects seaconnect 370w firmware. Severity is critical (CVSS 9.3). A denial of service vulnerability exists in the SeaMax remote configuration functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. Specially-crafted network packets can lead to denial of service. An attacker can send a malicious p

How urgent is CVE-2021-21965?

Priority 58/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

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References

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