How severe is CVE-2021-21965?

CVE-2021-21965 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.

Is CVE-2021-21965 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-21965?

CVE-2021-21965 affects Sealevel Seaconnect 370w Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21965?

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

When was CVE-2021-21965 published?

CVE-2021-21965 was published on 2022-02-04 and last updated on 2026-06-17.

CVE-2021-21965

CVE-2021-21965 is a critical-severity vulnerability in Sealevel Seaconnect 370w Firmware with a CVSS 3.x base score of 9.3. 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-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.3)
CVSS v2: 6.4
EPSS exploit prediction: 1% (59th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Sealevel Seaconnect 370w Firmware
Published: 2022-02-04
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-21965?: 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.
How severe is CVE-2021-21965?: CVE-2021-21965 has a CVSS 3.x base score of 9.3, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability high.
Is CVE-2021-21965 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (59th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-21965?: CVE-2021-21965 affects Sealevel Seaconnect 370w Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21965?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-21965 published?: CVE-2021-21965 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:*:*:*:*:*:*:*

More vulnerabilities in Sealevel Seaconnect 370w Firmware

CVE-2021-21961 — Critical (CVSS 10.0): A stack-based buffer overflow vulnerability exists in the NBNS functionality of Sealevel Systems, Inc. SeaConnect 370W…
CVE-2021-21960 — Critical (CVSS 10.0): A stack-based buffer overflow vulnerability exists in both the LLMNR functionality of Sealevel Systems, Inc. SeaConnect…
CVE-2021-21968 — High (CVSS 8.3): A file write vulnerability exists in the OTA update task functionality of Sealevel Systems, Inc. SeaConnect 370W…
CVE-2021-21970 — High (CVSS 8.1): An out-of-bounds write vulnerability exists in the HandleSeaCloudMessage functionality of Sealevel Systems, Inc.…
CVE-2021-21969 — High (CVSS 8.1): An out-of-bounds write vulnerability exists in the HandleSeaCloudMessage functionality of Sealevel Systems, Inc.…
CVE-2021-21962 — High (CVSS 8.1): A heap-based buffer overflow vulnerability exists in the OTA Update u-download functionality of Sealevel Systems, Inc.…

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