CVE-2020-1627Network attack vector

Sustained service interruption via flow-cache packet handling

Published Apr 8, 2020 · Updated Sep 16, 2024

Denial of service in Juniper Networks Junos OS on vMX and MX150 allows remote attackers to crash RIOT with crafted packets. The flow cache cannot handle packets requiring special microcode processing, and lu_reorder_send_packet_postproc() panics the RIOT forwarding daemon. Flow cache is enabled by default only in performance mode on vMX and MX150, and device-destined traffic can cause repeated crashes and sustained service interruption; transit traffic cannot trigger it.

CVSS severity7.5
High
EPSS probability1.32%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Juniper Networks Junos OS on vMX and MX150 allows remote attackers to crash RIOT with crafted packets. The flow cache cannot handle packets requiring special microcode processing, and lu_reorder_send_packet_postproc() panics the RIOT forwarding daemon. Flow cache is enabled by default only in performance mode on vMX and MX150, and device-destined traffic can cause repeated crashes and sustained service interruption; transit traffic cannot trigger it.

The record

CVE
CVE-2020-1627
Published
Apr 8, 2020
Updated
Sep 16, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 8, 2020CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=18.1 <18.1R3
  2. Affected versionversion=18.2 <18.2R3
  3. Affected versionversion=18.2X75 <18.2X75-D60
  4. Affected versionversion=18.3 <18.3R3
  5. Affected versionversion=18.4 <18.4R2
  6. Affected versionversion=19.1 <19.1R2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=18.1 <18.1R3; version=18.2 <18.2R3; version=18.2X75 <18.2X75-D60; version=18.3 <18.3R3; version=18.4 <18.4R2; version=19.1 <19.1R2

Published CVSS scores

7.5Juniper Networks, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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