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JunosOperating system · Juniper

CVE-2019-0063

HIGH · 7.5 CVSS v3.1 Published 2019-10-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
When an MX Series Broadband Remote Access Server (BRAS) is configured as a Broadband Network Gateway (BNG) with DHCPv6 enabled, jdhcpd might crash when receiving a specific crafted DHCP response message on a subscriber interface. The daemon automatically restarts without intervention, but continuous receipt of specific crafted DHCP messages will repeatedly crash jdhcpd, leading to an extended Denial of Service (DoS) condition. This issue only affects systems configured with DHCPv6 enabled. DHCPv4 is unaffected by this issue. This issue affects Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S5 on MX Series; 16.1 versions prior to 16.1R7-S5 on MX Series; 16.2 versions prior to 16.2R2-S10 on MX Series; 17.1 versions prior to 17.1R3-S1 on MX Series; 17.2 versions prior to 17.2R3-S2 on MX Series; 17.3 versions prior to 17.3R3-S6 on MX Series; 17.4 versions prior to 17.4R2-S5, 17.4R3 on MX Series; 18.1 versions prior to 18.1R3-S6 on MX Series; 18.2 versions prior to 18.2R2-S4, 18.2R3 on MX Series; 18.2X75 versions prior to 18.2X75-D50 on MX Series; 18.3 versions prior to 18.3R1-S5, 18.3R3 on MX Series; 18.4 versions prior to 18.4R2 on MX Series; 19.1 versions prior to 19.1R1-S2, 19.1R2 on MX 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 confidence

When an MX Series Broadband Remote Access Server (BRAS) is configured as a Broadband Network Gateway (BNG) with DHCPv6 enabled, the jdhcpd daemon crashes upon receiving a specific crafted DHCP response message on a subscriber interface. While the daemon auto-restarts, repeated receipt of crafted messages causes repeated crashes, resulting in an extended Denial of Service. DHCPv4 configurations are unaffected.

MitigationUpgrade Junos OS on affected MX Series devices to a patched version as specified in the vendor advisory. As an interim measure, consider disabling DHCPv6 if operationally feasible, though this may impact IPv6 subscriber services.

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:= 15.1= 16.1= 16.2= 17.1= 17.2= 17.3= 17.4= 18.1= 18.2= 18.2x75= 18.3= 18.4

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. Confirm device is MX Series hardware
    Run 'show chassis hardware' or 'show version' and verify the device model contains 'MX' (e.g., MX240, MX480, MX960)
    Affected if Device is not an MX Series device - this vulnerability only affects MX Series BRAS/BNG devices
  2. Check installed Junos version
    Run 'show version' and note the Junos OS version number (e.g., 18.2R1, 17.4R3)
    Affected if Version matches one of the affected versions: 15.1, 16.1, 16.2, 17.1, 17.2, 17.3, 17.4, 18.1, 18.2, 18.2x75, 18.3, 18.4 (any build suffix)
  3. Verify DHCPv6 is enabled
    Run 'show configuration system services dhcpv6' or search for 'dhcpv6' in the active configuration with 'show configuration | display set | match dhcpv6'
    Affected if DHCPv6 is actively configured and enabled - the vulnerability only triggers when DHCPv6 is running
  4. Confirm BNG/BRAS role is configured
    Run 'show configuration | display set | match bng' or 'show configuration | display set | match broadband-network-gateway' to search for BNG-specific service configuration
    Affected if Device is configured as a Broadband Network Gateway (BNG) - the vulnerability requires BNG role on a subscriber interface

Device is affected if it is an MX Series with Junos 15.1-18.4, has DHCPv6 enabled, and is configured as a BNG serving subscriber interfaces.

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 Junos OS on affected MX Series devices to a patched version as specified in the vendor advisory. As an interim measure, consider disabling DHCPv6 if operationally feasible, though this may impact IPv6 subscriber services.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,480
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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-2019-0063 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