HOMEVULNERABILITIESCVE-2016-4521
CRITICAL

CVE-2016-4521

CWE-200Published: May 31, 2016· Updated: Jun 17, 2026

9.8
CVSS v3.1

Official Description

Sixnet BT-5xxx and BT-6xxx M2M devices before 3.8.21 and 3.9.x before 3.9.8 have hardcoded credentials, which allows remote attackers to obtain access via unspecified vectors.

NVD Source

Technical Analysis

CVE-2016-4521 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.

From a weakness classification perspective (CWE-200): Information exposure vulnerabilities leak sensitive data to unauthorized actors.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected Vendors & Products

sixnet4 product(s)
bt-5 series cellular routerbt-6 series cellular routerbt-5 series cellular router firmwarebt-6 series cellular router firmware
Source: NVD CPE · 4 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttps://ics-cert.us-cert.gov/advisories/ICSA-16-147-02
ADVISORYhttps://ics-cert.us-cert.gov/advisories/ICSA-16-147-02

All References (2)

→
https://ics-cert.us-cert.gov/advisories/ICSA-16-147-02Third Party Advisory · US Government Resource
→
https://ics-cert.us-cert.gov/advisories/ICSA-16-147-02Third Party Advisory · US Government Resource

Quick Facts

CVE IDCVE-2016-4521
CVSS Score9.8 / 10
SeverityCRITICAL
WeaknessCWE-200
CISA KEVNo
Affected1 vendor(s)
PublishedMay 31, 2016

Related CVEs (CWE-200)

CVE-2008-1155
10.0
CVE-2008-1252
10.0
CVE-2026-27604
10.0
CVE-2026-40965
10.0
CVE-2025-22612
10.0
CVE-2011-0376
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2016-4521 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWATCH.COM. CVE data is provided under the NVD usage policy.
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