CVE-2016-5363
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 · uneditedThe IPTables firewall in OpenStack Neutron before 7.0.4 and 8.0.0 through 8.1.0 allows remote attackers to bypass an intended MAC-spoofing protection mechanism and consequently cause a denial of service or intercept network traffic via (1) a crafted DHCP discovery message or (2) crafted non-IP traffic.
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 confidenceOpenStack Neutron's IPTables firewall contains a flaw that allows attackers to bypass MAC-spoofing protection mechanisms. By sending specially crafted DHCP discovery messages or non-IP traffic, remote attackers can circumvent security controls and potentially cause denial of service or intercept network traffic.
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= 7.0.0= 7.0.1= 7.0.2= 7.0.3= 7.0.4= 8.0.0= 8.1.0CVSS 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
- Low
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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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Check installed Neutron versionRun `neutron --version` or query the package manager (e.g., `rpm -q neutron` or `dpkg -l neutron`) to obtain the installed version numberAffected if The version matches 7.0.0, 7.0.1, 7.0.2, 7.0.3, 7.0.4, 8.0.0, or 8.1.0
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Identify the active firewall driverCheck the Neutron configuration file (typically /etc/neutron/neutron.conf or /etc/neutron/fwaas_driver.ini) for the `firewall_driver` setting under the firewall or security group configuration sectionAffected if The firewall_driver is set to `neutron.agent.linux.iptables_firewall.OVSHybridIptablesFirewallDriver` or another iptables-based driver (not the Open vSwitch native driver)
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Verify MAC-spoofing rules exist for DHCPOn the compute node, list iptables rules for the security group chains (e.g., `sudo iptables -L -n -v | grep -i spoof` or inspect the neutron security group chain) and check if rules explicitly handle DHCP traffic (port 67/68) for anti-spoofingAffected if No specific anti-spoofing rule exists for DHCP traffic (UDP ports 67-68) in the iptables rules, or rules only cover IP traffic and not ARP/DHCP
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Confirm non-IP traffic handlingReview the iptables rules for the security group provider chain to see if there are rules that block or filter non-IP/non-ARP traffic, or check if all traffic types are subject to MAC-spoofing enforcementAffected if The iptables rules do not filter or block non-IP traffic (such as ARP, custom layer 2 frames) or there is no rule dropping traffic that fails MAC validation for non-IP protocols
A system is affected if it runs Neutron version 7.0.0-7.0.4 or 8.0.0-8.1.0 with an iptables-based firewall driver and lacks proper anti-MAC-spoofing rules for DHCP and non-IP traffic.
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 dataUpgrade OpenStack Neutron to version 7.0.4 or later, or 8.1.1 or later to obtain the patched code that properly enforces MAC-spoofing protection on all traffic types.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2016-5363 — 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-2016-5363 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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