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2020-04 Security Bulletin: Junos OS: vMX and MX150: Denial of Service vulnerability in packet processing (CVE-2020-1627)



Article ID: JSA11006 SECURITY_ADVISORIES Last Updated: 08 Apr 2020Version: 1.0
Product Affected:
This issue affects Junos OS 18.1, 18.2, 18.2X75, 18.3, 18.4, 19.1. Affected platforms: vMX and MX150.

A vulnerability in Juniper Networks Junos OS on vMX and MX150 devices may allow an attacker to cause a Denial of Service (DoS) by sending specific packets requiring special processing in microcode that the flow cache can't handle, causing the riot forwarding daemon to crash. By continuously sending the same specific packets, an attacker can repeatedly crash the riot process causing a sustained Denial of Service.

Flow cache is specific to vMX based products and the MX150, and is enabled by default in performance mode.

This issue can only be triggered by traffic destined to the device. Transit traffic will not cause the riot daemon to crash.

When the issue occurs, a core dump and riot log file entry are generated. For example:

/home/pfe/RIOT logs:
fpc0 riot[1888]: PANIC in lu_reorder_send_packet_postproc():
fpc0 riot[6655]: PANIC in lu_reorder_send_packet_postproc():

This issue affects Juniper Networks Junos OS:

  • 18.1 versions prior to 18.1R3 on vMX and MX150;
  • 18.2 versions prior to 18.2R3 on vMX and MX150;
  • 18.2X75 versions prior to 18.2X75-D60 on vMX and MX150;
  • 18.3 versions prior to 18.3R3 on vMX and MX150;
  • 18.4 versions prior to 18.4R2 on vMX and MX150;
  • 19.1 versions prior to 19.1R2 on vMX and MX150.

This issue does not affect Junos OS versions prior to 18.1R1.

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen during production usage.

This issue has been assigned CVE-2020-1627.


The following software releases have been updated to resolve this specific issue: 18.1R3, 18.2R3, 18.2X75-D60, 18.3R3, 18.4R2, 19.1R2, 19.2R1, 19.3R1, and all subsequent releases.

This issue is being tracked as 1423575.


There are no viable workarounds for this issue.

How to obtain fixed software:

Security vulnerabilities in Junos are fixed in the next available Maintenance Release of each supported Junos version. In some cases, a Maintenance Release is not planned to be available in an appropriate time-frame. For these cases, Service Releases are made available in order to be more timely. Security Advisory and Security Notices will indicate which Maintenance and Service  Releases contain fixes for the issues described. Upon request to JTAC, customers will be provided download instructions for a Service Release. Although Juniper does not provide formal Release Note documentation for a Service Release, a list of "PRs fixed" can be provided on request.
Modification History:
‚Äč2020-04-08: Initial publication
CVSS Score:
7.5 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Severity Level:
Severity Assessment:
Information for how Juniper Networks uses CVSS can be found at KB 16446 "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

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