Unauthenticated code execution via unchecked NBNS name length
Published Feb 4, 2022 · Updated Apr 15, 2025
Stack-based buffer overflow in SeaConnect 370W 1.3.34 allows remote attackers to execute code via a crafted NBNS query. The NBNS parser trusts an attacker-controlled one-byte name length and copies that many bytes into a 32-byte stack buffer without bounds checking. Network access to UDP port 137 is sufficient; the overflow can corrupt the saved link register and redirect execution.
Summary
What happened
Stack-based buffer overflow in SeaConnect 370W 1.3.34 allows remote attackers to execute code via a crafted NBNS query. The NBNS parser trusts an attacker-controlled one-byte name length and copies that many bytes into a 32-byte stack buffer without bounds checking. Network access to UDP port 137 is sufficient; the overflow can corrupt the saved link register and redirect execution.
The record
- CVE
- CVE-2021-21961
- Published
- Feb 4, 2022
- Updated
- Apr 15, 2025
- Vendor
- Sealevel Systems, Inc.
- Product
- SeaConnect 370W
- Classifications
- CWE-121, CWE-787, T1190
- 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
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- SeaConnect 370W NBNS overflow proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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