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JunosOperating system · Juniper

CVE-2019-0031

HIGH · 7.5 CVSS v3.1 Published 2019-04-10
Fix available
A fix is available. Upgrade to 17.4r2 / 18.1r2 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable 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
Specific IPv6 DHCP packets received by the jdhcpd daemon will cause a memory resource consumption issue to occur on a Junos OS device using the jdhcpd daemon configured to respond to IPv6 requests. Once started, memory consumption will eventually impact any IPv4 or IPv6 request serviced by the jdhcpd daemon, thus creating a Denial of Service (DoS) condition to clients requesting and not receiving IP addresses. Additionally, some clients which were previously holding IPv6 addresses will not have their IPv6 Identity Association (IA) address and network tables agreed upon by the jdhcpd daemon after the failover event occurs, which leads to more than one interface, and multiple IP addresses, being denied on the client. Affected releases are Juniper Networks Junos OS: 17.4 versions prior to 17.4R2; 18.1 versions prior to 18.1R2.

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 confidence

A memory consumption vulnerability in the jdhcpd daemon on Junos OS devices allows remote attackers to trigger excessive memory usage by sending specific IPv6 DHCP packets. Once memory consumption starts, it impacts servicing of both IPv4 and IPv6 DHCP requests, causing a DoS condition where clients cannot obtain IP addresses. Additionally, the memory issue causes IA (Identity Association) table inconsistencies after failover events, resulting in clients being denied multiple interface addresses.

MitigationUpgrade Junos OS to version 17.4R2 or later (for 17.4 branch) and 18.1R2 or later (for 18.1 branch) to patch the vulnerability in the jdhcpd daemon.

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
JunosOperating system
Affected:>= 17.4, < 17.4r2>= 18.1, < 18.1r2

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/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 checks

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

  1. Determine the Junos OS version
    Run 'show version' or 'request system software version' on the device
    Affected if The version falls within >= 17.4, < 17.4r2 or >= 18.1, < 18.1r2
  2. Verify the jdhcpd daemon is running
    Run 'show system processes' or check daemon status for jdhcpd
    Affected if The jdhcpd daemon is active on the device
  3. Check if IPv6 DHCP is configured
    Run 'show configuration' and look for 'system services dhcpv6' or similar DHCPv6 configuration statements
    Affected if IPv6 DHCP services are enabled on the device
  4. Inspect memory usage of the jdhcpd process
    Run 'show system processes extensive | match jdhcpd' to view memory consumption over time
    Affected if Memory usage is abnormally high or growing for the jdhcpd process
  5. Check for DHCP service degradation
    Run 'show dhcpv6 binding' or 'show dhcp server binding' to verify clients can obtain addresses
    Affected if Clients are failing to obtain IP addresses or IA table inconsistencies are present

If the device runs Junos OS version 17.4 through 17.4r1 or 18.1 through 18.1r1, has jdhcpd running with IPv6 DHCP enabled, and shows symptoms of memory issues or DHCP failures, the environment is affected by CVE-2019-0031.

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
Upgrade available Upgrade to 17.4r2 / 18.1r2 or later
Fixed in 17.4r218.1r2
Interim mitigation

Upgrade Junos OS to version 17.4R2 or later (for 17.4 branch) and 18.1R2 or later (for 18.1 branch) to patch the vulnerability in the jdhcpd daemon.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA3.0 h
19.0 hours of engineering $3,320
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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-2019-0031 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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data