Usg9500 FirmwareOperating system · Huawei

CVE-2016-4577

HIGH · 7.5 CVSS v3.0 Published 2016-05-23
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
No privileges Zero-click

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 · unedited
Buffer overflow in the Smart DNS functionality in the Huawei NGFW Module and Secospace USG6300, USG6500, USG6600, and USG9500 firewalls with software before V500R001C20SPC100 allows remote attackers to cause a denial of service or execute arbitrary code via a crafted packet, related to "illegitimate parameters."

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 · moderate confidence

Buffer overflow vulnerability in the Smart DNS functionality of Huawei NGFW and USG6300/6500/6600/9500 firewalls allows remote attackers to send crafted packets with illegitimate parameters, potentially causing denial of service or achieving arbitrary code execution.

MitigationUpgrade Huawei firewall software to V500R001C20SPC100 or later. If immediate patching is not feasible, consider filtering or rate-limiting DNS traffic at upstream network segments to reduce attack surface.

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
Usg9500 FirmwareOperating system
Affected:= v500r001c00
Ngfw Module FirmwareOperating system
Affected:= v500r001c00
Secospace Usg6300 FirmwareOperating system
Affected:= v500r001c00
Secospace Usg6600 FirmwareOperating system
Affected:= v500r001c00
Secospace Usg6500 FirmwareOperating system
Affected:= v500r001c00

CVSS 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
Adjacent
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.0/AV:A/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify device model and firmware version
    Access the firewall CLI or web interface and run 'display version' or check the system info page to retrieve the product model and firmware version
    Affected if The device model is USG6300, USG6500, USG6600, USG9500, or NGFW Module and the firmware version is exactly v500r001c00
  2. Confirm Smart DNS feature status
    Check the firewall configuration via CLI using 'display current-configuration' or via web interface under DNS/Forwarding settings to see if Smart DNS is enabled
    Affected if Smart DNS functionality is enabled on the device
  3. Verify DNS service configuration
    Inspect DNS-related configuration files or settings to confirm DNS traffic handling is active. Use 'display dns configuration' or similar DNS-related display commands
    Affected if DNS services are configured and active on the firewall

The device is affected if it is one of the affected models (USG6300/6500/6600/9500 or NGFW Module), runs firmware version v500r001c00 exactly, and has Smart DNS functionality enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade Huawei firewall software to V500R001C20SPC100 or later. If immediate patching is not feasible, consider filtering or rate-limiting DNS traffic at upstream network segments to reduce attack surface.

Fix this in Usg9500 Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2016-4577 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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