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JunosOperating system · Juniper

CVE-2020-1646

HIGH · 7.5 CVSS v3.1 Published 2020-07-17
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
On Juniper Networks Junos OS and Junos OS Evolved devices, processing a specific UPDATE for an EBGP peer can lead to a routing process daemon (RPD) crash and restart. This issue occurs only when the device is receiving and processing the BGP UPDATE for an EBGP peer. This issue does not occur when the device is receiving and processing the BGP UPDATE for an IBGP peer. However, the offending BGP UPDATE can originally come from an EBGP peer, propagates through the network via IBGP peers without causing crash, then it causes RPD crash when it is processed for a BGP UPDATE towards an EBGP peer. Repeated receipt and processing of the same specific BGP UPDATE can result in an extended Denial of Service (DoS) condition. This issue affects: Juniper Networks Junos OS: 17.3R3-S6, 17.4R2-S7, and 18.1R3-S7. Juniper Networks Junos OS Evolved 19.2R2-EVO and later versions, prior to 19.3R1-EVO. Other Junos OS releases are not affected.

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 Juniper Junos OS allows a specially crafted BGP UPDATE message destined for an EBGP peer to trigger a crash and restart of the routing process daemon (RPD). The malicious UPDATE can originate from an EBGP peer, propagate through IBGP peers without causing issues, then cause RPD crash when processed for an EBGP peer, enabling repeated DoS attacks.

MitigationApply vendor patches (Junos OS 17.3R3-S7, 17.4R3, 18.1R4+ or Junos OS Evolved 19.3R1-EVO+). Alternatively, implement BGP route filtering to drop suspicious or unexpected UPDATE messages from untrusted peers.

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:= 17.3= 17.4= 18.1
Junos Os EvolvedOperating system
Affected:= 19.2

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
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. Identify the Junos OS version
    Execute 'show version' or 'show version detail' on the device CLI and note the installed version number.
    Affected if The installed version matches 17.3, 17.4, 18.1, or 19.2 (OS Evolved) exactly.
  2. Confirm BGP protocol is configured
    Execute 'show configuration protocols bgp' to view the BGP configuration.
    Affected if BGP is actively configured on the device.
  3. Identify EBGP peer relationships
    Execute 'show bgp summary' or 'show bgp neighbor' to list all BGP peers and their types.
    Affected if Any peer is configured as an external BGP (EBGP) neighbor, as the vulnerability triggers when processing UPDATE messages for EBGP peers.
  4. Review RPD crash history
    Execute 'show system core-dumps' or check '/var/log/messages' for rpd crash events, looking for recent routing process daemon restarts.
    Affected if RPD has crashed or restarted repeatedly, especially after receiving BGP updates from EBGP peers.

You are affected if your device runs Junos version 17.3, 17.4, 18.1, or 19.2 (Evolved) and has EBGP peers configured, as the specially crafted BGP UPDATE message from an EBGP peer can trigger RPD crashes.

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 vendor patches (Junos OS 17.3R3-S7, 17.4R3, 18.1R4+ or Junos OS Evolved 19.3R1-EVO+). Alternatively, implement BGP route filtering to drop suspicious or unexpected UPDATE messages from untrusted peers.

Fix this in Junos Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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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-2020-1646 in production — separate from our analysis above.

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What this is

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What belongs here
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