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JunosOperating system · Juniper

CVE-2020-1604

MEDIUM · 5.3 CVSS v3.1 Published 2020-01-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
62/100
Remediation priority · Elevated
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 EX4300, EX4600, QFX3500, and QFX5100 Series, a vulnerability in the IP firewall filter component may cause the firewall filter evaluation of certain packets to fail. This issue only affects firewall filter evaluation of certain packets destined to the device Routing Engine (RE). This issue does not affect the Layer 2 firewall filter evaluation nor does it affect the Layer 3 firewall filter evaluation destined to connected hosts. This issue may occur when evaluating both IPv4 or IPv6 packets. This issue affects Juniper Networks Junos OS: 14.1X53 versions prior to 14.1X53-D12 on QFX5100 Series and EX4600 Series; 14.1X53 versions prior to 14.1X53-D52 on QFX3500 Series; 14.1X53 versions prior to 14.1X53-D48 on EX4300 Series; 15.1 versions prior to 15.1R7-S3 on EX4300 Series; 16.1 versions prior to 16.1R7 on EX4300 Series; 17.1 versions prior to 17.1R3 on EX4300 Series; 17.2 versions prior to 17.2R3 on EX4300 Series; 17.3 versions prior to 17.3R2-S5, 17.3R3 on EX4300 Series; 17.4 versions prior to 17.4R2 on EX4300 Series; 18.1 versions prior to 18.1R3 on EX4300 Series; 18.2 versions prior to 18.2R2 on EX4300 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

A vulnerability in the IP firewall filter component on EX4300, EX4600, QFX3500, and QFX5100 Series switches causes firewall filter evaluation to fail for certain IPv4 or IPv6 packets destined to the Routing Engine (RE). This allows affected traffic to potentially bypass configured firewall filters intended to protect the RE, while Layer 2 filters and Layer 3 filters for connected hosts remain unaffected.

MitigationApply the Junos OS software update corresponding to the affected version series as specified in the Juniper Networks advisory (14.1X53-D12/D52/D48, 15.1R7-S3, 16.1R7, 17.1R3, 17.2R3, 17.3R2-S5/17.3R3, 17.4R2, 18.1R3, 18.2R2).

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:= 14.1x53= 15.1= 16.1= 17.1= 17.2= 17.3= 17.4= 18.1= 18.2

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
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

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 model is affected
    Run 'show chassis hardware' or 'show version' to identify the switch model
    Affected if Model is EX4300, EX4600, QFX3500, or QFX5100
  2. Check Junos OS version
    Run 'show version' to display the installed Junos version
    Affected if Version matches 14.1X53, 15.1X, 16.1X, 17.1X, 17.2X, 17.3X, 17.4X, 18.1X, or 18.2X (specific subversions listed in advisory)
  3. Verify firewall filters protect the Routing Engine
    Run 'show configuration firewall' and check for filters applied to the loopback interface (lo0) or ingress filters targeting RE traffic
    Affected if Firewall filters are configured to filter traffic destined to the Routing Engine
  4. Check for IPv4 or IPv6 traffic to the Routing Engine
    Run 'show interfaces lo0' to verify the loopback interface is up, then monitor traffic with 'show firewall filter <filter-name>' to see if packets are being evaluated
    Affected if Device processes IPv4 or IPv6 packets destined to the RE through configured firewall filters

Device is affected if it is an EX4300/EX4600/QFX3500/QFX5100 running an affected Junos version AND has firewall filters configured to protect the Routing Engine that could be bypassed by IPv4/IPv6 traffic.

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

Apply the Junos OS software update corresponding to the affected version series as specified in the Juniper Networks advisory (14.1X53-D12/D52/D48, 15.1R7-S3, 16.1R7, 17.1R3, 17.2R3, 17.3R2-S5/17.3R3, 17.4R2, 18.1R3, 18.2R2).

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing8.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,800
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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-2020-1604 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