CVE-2021-21969
CVE-2021-21969 is a high-severity vulnerability in Sealevel Seaconnect 370w Firmware with a CVSS 3.x base score of 8.1. 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: High (CVSS 3.x base score 8.1)
- CVSS v2: 6.8
- EPSS exploit prediction: 1% (55th percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-787
- Affected product: Sealevel Seaconnect 370w Firmware
- Published:
- Last modified:
Description
An out-of-bounds write vulnerability exists in the HandleSeaCloudMessage functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. The HandleIncomingSeaCloudMessage function uses at [4] the json_object_get_string to populate the p_payload global variable. The p_payload is only 0x100 bytes long, and the total MQTT message could be up to 0x201 bytes. Because the function json_object_get_string will fill str based on the length of the json’s value and not the actual str size, this would result in a possible out-of-bounds write.
Frequently asked questions
- What is CVE-2021-21969?
- An out-of-bounds write vulnerability exists in the HandleSeaCloudMessage functionality of Sealevel Systems, Inc. SeaConnect 370W v1.3.34. The HandleIncomingSeaCloudMessage function uses at [4] the json_object_get_string to populate the p_payload global variable. The p_payload is only 0x100 bytes long, and the total MQTT message could be up to 0x201 bytes. Because the function json_object_get_string will fill str based on the length of the json’s value and not the actual str size, this would result in a possible out-of-bounds write.
- How severe is CVE-2021-21969?
- CVE-2021-21969 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2021-21969 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (55th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2021-21969?
- CVE-2021-21969 affects Sealevel Seaconnect 370w Firmware. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2021-21969?
- 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-2021-21969 published?
- CVE-2021-21969 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:*:*:*:*:*:*:*
More vulnerabilities in Sealevel Seaconnect 370w Firmware
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- 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-2021-21965 — Critical (CVSS 9.3): A denial of service vulnerability exists in the SeaMax remote configuration functionality of Sealevel Systems, Inc.…
- 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-2021-21962 — 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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