CVE-2021-21962
A heap-based buffer overflow vulnerability exists in the OTA Update u-download functionality of...
A heap-based buffer overflow vulnerability exists in the OTA Update u-download functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A series of specially-crafted MQTT payloads can lead to remote code execution. An attacker must perform a man-in-the-middle attack in order to trigger this vulnerability.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
A heap-based buffer overflow vulnerability exists in the OTA Update u-download functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A series of specially-crafted MQTT payloads can lead to remote code execution. An attacker must perform a man-in-the-middle attack in order to trigger this vulnerability.
- Record
CVE-2021-21962- CVSS 3.0
- 9.0 Critical
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-122
- Updated
- 2026-11-02
EUVDEUVD-2021-9133
A heap-based buffer overflow vulnerability exists in the OTA Update u-download functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A series of specially-crafted MQTT payloads can lead to remote code execution. An attacker must perform a man-in-the-middle attack in order to trigger this vulnerability.
- Record
EUVD-2021-9133- CVSS 3.0
- 9.0 Critical
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-pcpq-5r7p-4983
A heap-based buffer overflow vulnerability exists in the OTA Update u-download functionality of...
A heap-based buffer overflow vulnerability exists in the OTA Update u-download functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A series of specially-crafted MQTT payloads can lead to remote code execution. An attacker must perform a man-in-the-middle attack in order to trigger this vulnerability.
- Record
GHSA-pcpq-5r7p-4983- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-787
- Updated
- 2026-11-02
NVD
A heap-based buffer overflow vulnerability exists in the OTA Update u-download functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. A series of specially-crafted MQTT payloads can lead to remote code execution. An attacker must perform a man-in-the-middle attack in order to trigger this vulnerability.
- Record
CVE-2021-21962- CVSS 3.1
- 8.1 High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 3.0
- 9.0 Critical
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H - CVSS 2.0
- 6.8 Medium
AV:N/AC:M/Au:N/C:P/I:P/A:P - Weakness
- CWE-122, CWE-787
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-21962 is a critical vulnerability (CVSS 9.0) in Sealevel Seaconnect 370w Firmware, published February 4, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.01%, the 80th percentile. No source names a fixed version.