How severe is CVE-2016-5363?

CVE-2016-5363 has a CVSS score of 8.2/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2016-5363?

CVE-2016-5363 affects the following packages: neutron (PyPI), neutron (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2016-5363?

Update neutron to 7.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-5363 is resolved across your whole dependency graph.

How do I detect CVE-2016-5363 in my PyPI dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for neutron, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2016-5363 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2016-5363 actively exploited in the wild?

No public exploit code has been indexed for CVE-2016-5363 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2016-5363?

CVE-2016-5363 has an EPSS (Exploit Prediction Scoring System) score of 3.3%, placing it in the 88th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2016-5363?

CVE-2016-5363 is classified as CWE-254 (CWE-254). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2016-5363 published, and has it been updated?

CVE-2016-5363 was published on June 17, 2016 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐍

🐍 PyPI

Not in CISA KEV

HIGH severity

CVE-2016-5363 — neutron

HIGHFix: openstack/neutron@5853af9

CVE-2016-5363 is a high-severity (CVSS 8.2) CWE-254 vulnerability in neutron. A fix is available for neutron — see the affected versions and patch details below.

OpenStack Neutron Intended MAC-spoofing protection mechanism bypass

Also known asGHSA-9pp3-cvmq-9p22PYSEC-2026-852

Published

Jun 17, 2016

Updated

Oct 24, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Oct 27, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

3.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs88th percentile — riskier than 88% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

🐍neutron🐍neutron

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

The 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.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`neutron`	all versions	7.1.0`pip install --upgrade 'neutron==7.1.0'`
🐍PyPI	`neutron`	≥ 8.0.0&&< 8.1.0	8.1.0`pip install --upgrade 'neutron==8.1.0'`

Affected Products

1 product · 7 configurations

Application

neutronopenstack

7 versions

7.0.07.0.17.0.27.0.37.0.48.0.08.1.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for neutron, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update neutron to 7.1.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2016-5363 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatLow

Product	Fixed in	Advisory
Red Hat Enterprise Linux OpenStack Platform 7.0 (Kilo) for RHEL 7	`openstack-neutron-0:2015.1.4-2.el7ost`	RHSA-2016:1474
Red Hat OpenStack Platform 8.0 (Liberty)	`openstack-neutron-1:7.0.4-11.el7ost`	RHSA-2016:1473

Frequently Asked Questions

The IPTables firewall in OpenStack Neutron up to 7.0.4 and 8.x before 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.

O3 Security · Impact-Aware SCA

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