CVE-2015-6016
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedZyXEL P-660HW-T1 2 devices with ZyNOS firmware 3.40(AXH.0), PMG5318-B20A devices with firmware 1.00AANC0b5, and NBG-418N devices have a default password of 1234 for the admin account, which allows remote attackers to obtain administrative access via unspecified vectors.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceMultiple ZyXEL device models (P-660HW-T1 2, PMG5318-B20A, NBG-418N) ship with a hardcoded default administrative password '1234' for the admin account. Attackers with network access can authenticate remotely using these default credentials to gain full administrative control over the affected devices.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE dataall versions= 3.40\(axh.0\)= v100aanc0b5CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Identify your ZyXEL device modelLog into the device web interface or check the device label/model number. Common access paths: web browser to the device's IP address, or check physical device labeling.Affected if The device model is NBG-418N, P-660HW-T1, or PMG5318-B20A
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Check the installed firmware versionIn the device web interface, navigate to Status or System Info section to view the firmware version. This may also be accessible via SNMP or the device's administration CLI.Affected if Firmware version equals 3.40(axh.0) for Zynos, equals v100aanc0b5 for PMG5318-B20A, or for NBG-418N any version (all versions affected)
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Verify the admin account passwordAttempt to log into the device admin interface using the username 'admin' and password '1234', or examine the user account configuration if you have existing admin access.Affected if Authentication succeeds with default credentials 'admin'/'1234', indicating the default password has not been changed
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Confirm remote administration is accessibleCheck the device security or firewall settings for remote management/RWeb/WEB configuration. Verify if the admin interface is reachable from external network interfaces (WAN).Affected if Remote administration is enabled and the device is accessible from untrusted networks
You are affected if your ZyXEL device is one of the specified models, runs an affected firmware version, and retains the default password '1234' with remote administration accessible from the network.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataImmediately change the default admin password on all affected devices to a strong, unique password. If remote administration is not required, disable it. Check ZyXEL for available firmware updates that may address this default credential issue.
- Consultation2.0 h
- Implementation2.0 h
- Testing1.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2015-6016 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2015-6016 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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