CVE-2021-0288: A vulnerability in the processing of specific MPLS packets in Juniper Networks Junos OS on MX Series and EX9200 Series devices with Trio-based MPCs (M...

Description

A vulnerability in the processing of specific MPLS packets in Juniper Networks Junos OS on MX Series and EX9200 Series devices with Trio-based MPCs (Modular Port Concentrators) may cause FPC to crash and lead to a Denial of Service (DoS) condition. Continued receipt of this packet will sustain the Denial of Service (DoS) condition. This issue only affects MX Series and EX9200 Series with Trio-based PFEs (Packet Forwarding Engines). This issue affects Juniper Networks Junos OS on MX Series, EX9200 Series: 17.3 versions prior to 17.3R3-S12; 17.4 versions prior to 17.4R2-S13, 17.4R3-S5; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R3-S8; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R2-S8, 18.4R3-S8; 19.1 versions prior to 19.1R3-S5; 19.2 versions prior to 19.2R3-S2; 19.3 versions prior to 19.3R2-S6, 19.3R3-S3; 19.4 versions prior to 19.4R1-S4, 19.4R2-S4, 19.4R3-S2; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R2-S2, 20.2R3; 20.3 versions prior to 20.3R2; 20.4 versions prior to 20.4R2;

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.38%

29.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions	Update
Juniper	Junos	17.3	—
Juniper	Junos	17.4	—
Juniper	Junos	18.1	—
Juniper	Junos	18.2	—
Juniper	Junos	18.3	—
Juniper	Junos	18.4	—
Juniper	Junos	19.1	—
Juniper	Junos	19.2	—
Juniper	Junos	19.3	—
Juniper	Junos	19.4	R1
Juniper	Junos	20.1	R1
Juniper	Junos	20.2	R1
Juniper	Junos	20.3	R1
Juniper	Junos	20.4	R1

References

https://kb.juniper.net/JSA11190Vendor Advisory
https://kb.juniper.net/JSA11190Vendor Advisory

Timeline

Published: Jul 15, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-0288?

A vulnerability in the processing of specific MPLS packets in Juniper Networks Junos OS on MX Series and EX9200 Series devices with Trio-based MPCs (Modular Port Concentrators) may cause FPC to crash and lead to a Denial of Service (DoS) condition. Continued receipt of this packet will sustain the Denial of Service (DoS) condition. This issue only affects MX Series and EX9200 Series with Trio-based PFEs (Packet Forwarding Engines). This issue affects Juniper Networks Junos OS on MX Series, EX9200 Series: 17.3 versions prior to 17.3R3-S12; 17.4 versions prior to 17.4R2-S13, 17.4R3-S5; 18.1 versions prior to 18.1R3-S13; 18.2 versions prior to 18.2R3-S8; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R2-S8, 18.4R3-S8; 19.1 versions prior to 19.1R3-S5; 19.2 versions prior to 19.2R3-S2; 19.3 versions prior to 19.3R2-S6, 19.3R3-S3; 19.4 versions prior to 19.4R1-S4, 19.4R2-S4, 19.4R3-S2; 20.1 versions prior to 20.1R3; 20.2 versions prior to 20.2R2-S2, 20.2R3; 20.3 versions prior to 20.3R2; 20.4 versions prior to 20.4R2;

How severe is CVE-2021-0288?

CVE-2021-0288 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.38% probability of exploitation in the next 30 days.

How do I fix CVE-2021-0288?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.