CVE-2019-0033
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 · uneditedA firewall bypass vulnerability in the proxy ARP service of Juniper Networks Junos OS allows an attacker to cause a high CPU condition leading to a Denial of Service (DoS). This issue affects only IPv4. Affected releases are Juniper Networks Junos OS: 12.1X46 versions above and including 12.1X46-D25 prior to 12.1X46-D71, 12.1X46-D73 on SRX Series; 12.3X48 versions prior to 12.3X48-D50 on SRX Series; 15.1X49 versions prior to 15.1X49-D75 on SRX Series.
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 confidenceA firewall bypass vulnerability exists in the proxy ARP service of Juniper Networks Junos OS on SRX Series devices. An attacker can exploit this flaw to bypass firewall controls and trigger high CPU consumption, resulting in denial of service. The vulnerability affects only IPv4 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>= 12.1x46, <= 12.1x46-d10>= 12.1x46-d25, < 12.1x46-d71>= 12.3x48, < 12.3x48-d50>= 15.1x49, < 15.1x49-d75CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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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Identify device modelRun 'show chassis hardware' or 'show system information' to confirm this is an SRX Series deviceAffected if Device is not an SRX Series device - the vulnerability only affects SRX Series appliances
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Check installed Junos versionRun 'show version' to obtain the exact Junos OS version numberAffected if Version falls within any of these ranges: 12.1X46 through 12.1X46-D10, 12.1X46-D25 through 12.1X46-D70, 12.3X48 through 12.3X48-D49, or 15.1X49 through 15.1X49-D74
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Verify proxy ARP is enabledRun 'show configuration | display set | match proxy-arp' to check if proxy ARP is configured on any interfaceAffected if No proxy ARP configuration is found - the vulnerability only applies when proxy ARP is enabled
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Confirm IPv4 proxy ARP on interfacesRun 'show configuration interfaces' and look for 'family inet proxy-arp' under interface unitsAffected if IPv4 proxy ARP (family inet proxy-arp) is configured on any interface - this is the specific attack surface
A user is affected if they have an SRX Series device running an affected Junos version with IPv4 proxy ARP enabled on at least one interface
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 data12.1x46-d7112.3x48-d5015.1x49-d75
Upgrade Junos OS to the fixed versions: 12.1X46-D71 or later (12.1X46-D73), 12.3X48-D50 or later, or 15.1X49-D75 or later. Prior to upgrading, test the upgrade in a lab environment and schedule a maintenance window.
- Consultation3.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2019-0033 — 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-2019-0033 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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