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JunosOperating system · Juniper

CVE-2020-1641

MEDIUM · 6.5 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 →
70/100
Remediation priority · Elevated
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
A Race Condition vulnerability in Juniper Networks Junos OS LLDP implementation allows an attacker to cause LLDP to crash leading to a Denial of Service (DoS). This issue occurs when crafted LLDP packets are received by the device from an adjacent device. Multiple LACP flaps will occur after LLDP crashes. An indicator of compromise is to evaluate log file details for lldp with RLIMIT. Intervention should occur before 85% threshold of used KB versus maximum available KB memory is reached. show log messages | match RLIMIT | match lldp | last 20 Matching statement is " /kernel: %KERNEL-[number]: Process ([pid #],lldpd) has exceeded 85% of RLIMIT_DATA: " with [] as variable data to evaluate for. This issue affects: Juniper Networks Junos OS: 12.3 versions prior to 12.3R12-S15; 12.3X48 versions prior to 12.3X48-D95; 15.1 versions prior to 15.1R7-S6; 15.1X49 versions prior to 15.1X49-D200; 15.1X53 versions prior to 15.1X53-D593; 16.1 versions prior to 16.1R7-S7; 17.1 versions prior to 17.1R2-S11, 17.1R3-S2; 17.2 versions prior to 17.2R1-S9, 17.2R3-S3; 17.3 versions prior to 17.3R2-S5, 17.3R3-S6; 17.4 versions prior to 17.4R2-S4, 17.4R3; 18.1 versions prior to 18.1R3-S5; 18.2 versions prior to 18.2R2-S7, 18.2R3; 18.2X75 versions prior to 18.2X75-D12, 18.2X75-D33, 18.2X75-D50, 18.2X75-D420; 18.3 versions prior to 18.3R1-S7, 18.3R2-S3, 18.3R3; 18.4 versions prior to 18.4R1-S5, 18.4R2; 19.1 versions prior to 19.1R1-S4, 19.1R2.

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 race condition in the Junos OS LLDP (Link Layer Discovery Protocol) implementation allows an adjacent attacker to send crafted LLDP packets that cause the lldpd process to crash, resulting in Denial of Service. The crash is preceded by the process exceeding 85% of RLIMIT_DATA memory, and causes cascading LACP (Link Aggregation Control Protocol) flaps on affected interfaces.

MitigationApply the appropriate Junos OS software patch from the vendor's advisory. Until patched, monitor logs for the RLIMIT indicator and consider disabling LLDP on untrusted or external-facing interfaces to reduce attack surface.

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:= 12.3= 12.3x48= 15.1= 15.1x49= 15.1x53= 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
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/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. Verify LLDP is enabled on the device
    Run 'show protocols lldp' or check interface configurations for 'set protocols lldp' entries. On Junos, use 'show lldp diagnostics' to see LLDP status.
    Affected if LLDP is enabled on any interface - the vulnerability only affects systems where LLDP is running
  2. Confirm the Junos OS version
    Run 'show version' or 'show version detail' to obtain the installed Junos version.
    Affected if The installed version matches one of: 12.3, 12.3x48, 15.1, 15.1x49, 15.1x53, 16.1, 17.1, 17.2, 17.3, 17.4, 18.1, or 18.2
  3. Check for lldpd process restarts or crashes
    Run 'show system processes extensive | match lldpd' to view lldpd process status. Review logs with 'show log messages' for 'lldpd' crash entries.
    Affected if The lldpd process has crashed or shows frequent restarts, especially if accompanied by memory exhaustion indicators
  4. Look for RLIMIT_DATA memory warning indicators
    Review system logs for messages containing 'RLIMIT' or '85%' related to the lldpd process. Use 'show log messages | match "lldpd"| match "RLIMIT"'.
    Affected if Logs show lldpd process exceeding 85% of RLIMIT_DATA memory before crashes
  5. Check for LACP interface flaps
    Run 'show lacp interfaces' or review logs for 'LACP' flap messages on aggregated ethernet interfaces.
    Affected if Unusual LACP flaps are occurring on interfaces, which may indicate cascading effects from lldpd crashes

A device is likely affected if it runs a vulnerable Junos version (12.3 through 18.2), has LLDP enabled, and shows lldpd process crashes or memory pressure indicators.

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 appropriate Junos OS software patch from the vendor's advisory. Until patched, monitor logs for the RLIMIT indicator and consider disabling LLDP on untrusted or external-facing interfaces to reduce attack surface.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,840
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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-2020-1641 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
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