How severe is CVE-2021-21964?

CVE-2021-21964 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-21964 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21964?

CVE-2021-21964 affects Sealevel Seaconnect 370w Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21964?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-21964 published?

CVE-2021-21964 was published on 2022-02-04 and last updated on 2026-06-17.

CVE-2021-21964

CVE-2021-21964 is a high-severity vulnerability in Sealevel Seaconnect 370w Firmware with a CVSS 3.x base score of 7.4. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-306.

Key facts

Severity: High (CVSS 3.x base score 7.4)
CVSS v2: 7.1
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Sealevel Seaconnect 370w Firmware
Published: 2022-02-04
Last modified: 2026-06-17

Description

A denial of service vulnerability exists in the Modbus 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.

Frequently asked questions

What is CVE-2021-21964?: A denial of service vulnerability exists in the Modbus 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.
How severe is CVE-2021-21964?: CVE-2021-21964 has a CVSS 3.x base score of 7.4, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-21964 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (49th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21964?: CVE-2021-21964 affects Sealevel Seaconnect 370w Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21964?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-21964 published?: CVE-2021-21964 was published on 2022-02-04 and last updated on 2026-06-17.

References

https://talosintelligence.com/vulnerability_reports/TALOS-2021-1392

Affected products (1)

cpe:2.3:o:sealevel:seaconnect_370w_firmware:1.3.34:*:*:*:*:*:*:*

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