On Juniper Networks EX4300-MP Series, EX4600 Series, EX4650 Series, QFX5K Series deployed as a Virtual Chassis with a specific Layer 2 circuit configuration, Packet Forwarding Engine manager (FXPC) process may crash and restart upon receipt of specific layer 2 frames.

Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition.

This issue affects Juniper Networks Junos OS on EX4300-MP Series, EX4600 Series, EX4650 Series, QFX5K Series:

• 15.1 versions prior to 15.1R7-S9;
• 17.3 versions prior to 17.3R3-S11;
• 17.4 versions prior to 17.4R2-S13, 17.4R3-S4, 17.4R3-S5;
• 18.2 versions prior to 18.2R3-S8;
• 18.3 versions prior to 18.3R3-S4;
• 18.4 versions prior to 18.4R2-S7, 18.4R3-S6;
• 19.1 versions prior to 19.1R3-S4;
• 19.2 versions prior to 19.2R1-S6, 19.2R3-S1;
• 19.3 versions prior to 19.3R3-S1;
• 19.4 versions prior to 19.4R2-S4, 19.4R3-S1;
• 20.1 versions prior to 20.1R2;
• 20.2 versions prior to 20.2R2, 20.2R3;
• 20.3 versions prior to 20.3R1-S2, 20.3R2;

The examples of the configuration stanza affected by this issue is as follows:

used together with

or

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-2021-0237 .

The following software releases have been updated to resolve this specific issue: 15.1R7-S9, 17.3R3-S11, 17.4R2-S13, 17.4R3-S4, 17.4R3-S5, 18.3R3-S4, 18.4R2-S7, 18.4R3-S6, 19.1R3-S4, 19.2R1-S6, 19.2R3-S1, 19.3R3-S1, 19.4R2-S4, 19.4R3-S1, 20.1R2, 20.2R2, 20.2R3, 20.3R1-S2, 20.3R2, 20.4R1, and all subsequent releases.

This issue is being tracked as 1528409 .

Software releases or updates are available for download at https://support.juniper.net/support/downloads/

There are no viable workarounds for this issue.

2021-04-14: Initial Publication.

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2021-0237 at cve.mitre.org