dbcve.org
JunosOperating system · Juniper

CVE-2019-0040

CRITICAL · 9.1 CVSS v3.1 Published 2019-04-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
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
On Junos OS, rpcbind should only be listening to port 111 on the internal routing instance (IRI). External packets destined to port 111 should be dropped. Due to an information leak vulnerability, responses were being generated from the source address of the management interface (e.g. fxp0) thus disclosing internal addressing and existence of the management interface itself. A high rate of crafted packets destined to port 111 may also lead to a partial Denial of Service (DoS). Note: Systems with fxp0 disabled or unconfigured are not vulnerable to this issue. This issue only affects Junos OS releases based on FreeBSD 10 or higher (typically Junos OS 15.1+). Administrators can confirm whether systems are running a version of Junos OS based on FreeBSD 10 or higher by typing: user@junos> show version | match kernel JUNOS OS Kernel 64-bit [20181214.223829_fbsd-builder_stable_10] Affected releases are Juniper Networks Junos OS: 15.1 versions prior to 15.1F6-S12, 15.1R7-S4; 15.1X53 versions prior to 15.1X53-D236; 16.1 versions prior to 16.1R7-S1; 16.2 versions prior to 16.2R2-S9; 17.1 versions prior to 17.1R3; 17.2 versions prior to 17.2R1-S8; 17.3 versions prior to 17.3R2; 17.4 versions prior to 17.4R1-S1, 17.4R1-S7, 17.4R2. This issue does not affect Junos OS releases prior to 15.1.

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

An information leak vulnerability in Junos OS rpcbind causes responses to be sent from the management interface (fxp0) source address instead of the internal routing instance (IRI), exposing internal network addressing and the existence of the management interface. Additionally, high-rate crafted packets to port 111 can cause partial denial of service. Only affects systems with fxp0 enabled and Junos OS releases 15.1+ based on FreeBSD 10.

MitigationUpgrade to the fixed Junos OS versions specified in the advisory, or disable/unconfigure the fxp0 management interface if upgrade is not immediately feasible.

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= 15.1x53= 16.1= 16.2= 17.1= 17.2= 17.3= 17.4

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
High
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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. Verify if fxp0 management interface is configured
    Run 'show interfaces fxp0' or check the configuration with 'show configuration interfaces fxp0'
    Affected if fxp0 interface exists and is enabled in the configuration (status shows 'up' or configuration is present)
  2. Confirm Junos OS version
    Run 'show version' or 'show version detail' to obtain the installed Junos OS release version
    Affected if Version matches 15.1, 15.1x53, 16.1, 16.2, 17.1, 17.2, 17.3, or 17.4 (all based on FreeBSD 10)
  3. Verify rpcbind service status
    Run 'show system processes rpcbind' or check via 'show services rpcbind status' if available
    Affected if rpcbind daemon is running and listening on port 111

System is affected if fxp0 management interface is configured/enabled AND the Junos OS version is one of the listed affected releases (15.1 through 17.4), since the information leak only occurs when both conditions are met.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to the fixed Junos OS versions specified in the advisory, or disable/unconfigure the fxp0 management interface if upgrade is not immediately feasible.

Recommended fix High confidence

Upgrade to Junos OS 15.1F6-S12/15.1R7-S4, 15.1X53-D236, 16.1R7-S1, 16.2R2-S9, 17.1R3, 17.2R1-S8, 17.3R2, or 17.4R1-S1/17.4R1-S7/17.4R2 (or later stable releases)

  1. 1. Verify the current Junos OS version by running: show version | match kernel
  2. 2. Confirm whether fxp0 (management interface) is enabled: show interfaces fxp0
  3. 3. If fxp0 is disabled or unconfigured, the system is not vulnerable to this issue
  4. 4. If fxp0 is configured, determine the current Junos release branch (15.1, 15.1X53, 16.1, 16.2, 17.1, 17.2, 17.3, or 17.4)
  5. 5. Upgrade to the appropriate fixed release for your branch: 15.1F6-S12 or later, 15.1R7-S4 or later, 15.1X53-D236 or later, 16.1R7-S1 or later, 16.2R2-S9 or later, 17.1R3 or later, 17.2R1-S8 or later, 17.3R2 or later, or 17.4R1-S1/17.4R1-S7/17.4R2 or later
  6. 6. After upgrade, verify the fix by confirming rpcbind only responds on the IRI interface and not from fxp0
  7. 7. Alternatively, as a configuration mitigation, ensure fxp0 is disabled if not required, or implement firewall filters to drop external packets destined to port 111
Caveat Review Junos OS release notes for any compatibility issues or behavioral changes between current and target release versions

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2019-0040 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2019-0040 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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