CVE-2016-4087
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 · uneditedHuawei S12700 switches with software before V200R008C00SPC500 and S5700 switches with software before V200R005SPH010, when the debug switch is enabled, allows remote attackers to cause a denial of service or execute arbitrary code via crafted DNS packets.
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 confidenceThis is a pre-authentication remote code execution vulnerability in Huawei S12700 and S5700 switches. When the debug switch is enabled, the device's DNS packet processing logic contains a flaw that allows remote attackers to send specially crafted DNS packets leading to denial of service or arbitrary code execution. The attack requires no authentication and can be exploited remotely.
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 data= v200r005c00spc300= v200r001c00= v200r002c00spc100= v200r003c00spc300= v200r005c00CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:H/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 device model and confirm it is S12700 or S5700Run 'display device' or 'display version' command on the Huawei switch to confirm the exact model numberAffected if Device is not an S12700 or S5700 series switch - this CVE only affects those specific models
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Check firmware version against affected releasesRun 'display version' command and compare the displayed software version to the affected versions: S12700 v200r005c00spc300, S5700 v200r001c00, v200r002c00spc100, v200r003c00spc300, or v200r005c00Affected if The displayed firmware version matches one of the listed affected versions exactly
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Verify if debug/diagnostic switch is enabledRun 'display diagnostic-information' or 'display debugging' command to check if any debugging or diagnostic features are currently active on the deviceAffected if Debug or diagnostic functionality is enabled - the vulnerability requires the debug switch to be active for exploitation
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Confirm DNS service is configured on the deviceRun 'display current-configuration | include dns' or 'display ip interface' to check if DNS-related features or DNS relay/proxy is configured on the switchAffected if DNS service, DNS relay, or DNS proxy features are enabled - the vulnerability exists in the DNS packet processing logic
You are affected if you have an S12700 or S5700 switch running an affected firmware version with the debug/diagnostic switch enabled and DNS services configured on the device.
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 dataDisable the debug switch on affected devices if not required for troubleshooting, and upgrade to the patched software versions (V200R008C00SPC500 for S12700, V200R005SPH010 for S5700). Additionally, filter DNS traffic from untrusted external sources at network perimeter as a defense-in-depth measure.
- Consultation6.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2016-4087 — 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-2016-4087 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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- Version or environment caveats, and links to real fixes
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