How severe is CVE-2021-21971?

CVE-2021-21971 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2021-21971 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-2021-21971?

CVE-2021-21971 affects Sealevel Seaconnect 370w Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-21971?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-21971 published?

CVE-2021-21971 was published on 2022-02-04 and last updated on 2026-06-17.

CVE-2021-21971

CVE-2021-21971 is a medium-severity vulnerability in Sealevel Seaconnect 370w Firmware with a CVSS 3.x base score of 5.9. 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-787.

Key facts

Severity: Medium (CVSS 3.x base score 5.9)
CVSS v2: 4.3
EPSS exploit prediction: 1% (49th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-787
Affected product: Sealevel Seaconnect 370w Firmware
Published: 2022-02-04
Last modified: 2026-06-17

Description

An out-of-bounds write vulnerability exists in the URL_decode functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A specially-crafted MQTT payload can lead to an out-of-bounds write. An attacker can perform a man-in-the-middle attack to trigger this vulnerability.

Frequently asked questions

What is CVE-2021-21971?: An out-of-bounds write vulnerability exists in the URL_decode functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A specially-crafted MQTT payload can lead to an out-of-bounds write. An attacker can perform a man-in-the-middle attack to trigger this vulnerability.
How severe is CVE-2021-21971?: CVE-2021-21971 has a CVSS 3.x base score of 5.9, rated medium severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2021-21971 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-2021-21971?: CVE-2021-21971 affects Sealevel Seaconnect 370w Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-21971?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-21971 published?: CVE-2021-21971 was published on 2022-02-04 and last updated on 2026-06-17.

References

Affected products (1)

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

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