Memory corruption via oversized MQTT payload
Published Feb 4, 2022 · Updated Apr 15, 2025
Out-of-bounds write in Sealevel SeaConnect 370W 1.3.34 allows man-in-the-middle attackers to corrupt memory through a crafted MQTT payload. HandleIncomingSeaCloudMessage copies the JSON payload value into the 0x100-byte p_payload buffer using json_object_get_string, which writes according to the value length rather than the destination size. Exploitation requires interception and injection of traffic for the device's subscribed MQTT topic; the report demonstrates memory corruption but no data disclosure or service interruption.
Summary
What happened
Out-of-bounds write in Sealevel SeaConnect 370W 1.3.34 allows man-in-the-middle attackers to corrupt memory through a crafted MQTT payload. HandleIncomingSeaCloudMessage copies the JSON payload value into the 0x100-byte p_payload buffer using json_object_get_string, which writes according to the value length rather than the destination size. Exploitation requires interception and injection of traffic for the device's subscribed MQTT topic; the report demonstrates memory corruption but no data disclosure or service interruption.
The record
- CVE
- CVE-2021-21969
- Published
- Feb 4, 2022
- Updated
- Apr 15, 2025
- Vendor
- Sealevel Systems, Inc.
- Product
- SeaConnect 370W
- Classifications
- CWE-787, CWE-120, T1557
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 4, 2022CVE publishedPublication date reported by the CVE source.
- Apr 15, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=Sealevel Systems, Inc. SeaConnect 370W v1.3.34
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
- Cisco Talos crafted MQTT payload demonstrationproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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