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2021-01 Security Bulletin: EX and QFX5K Series: Storm Control does not work as expected when Redundant Trunk Group is configured (CVE-2021-0203)



Article ID: JSA11093 SECURITY_ADVISORIES Last Updated: 13 Jan 2021Version: 2.0
Product Affected:
This issue affects Junos OS 15.1, 16.1, 17.2, 17.3, 17.4, 18.1, 18.2, 18.3, 18.4, 19.1, 19.2, 19.3, 19.4, 20.1. Affected platforms: EX Series, QFX5K Series.

On Juniper Networks EX and QFX5K Series platforms configured with Redundant Trunk Group (RTG), Storm Control profile applied on the RTG interface might not take affect when it reaches the threshold condition.

Storm Control enables the device to monitor traffic levels and to drop broadcast, multicast, and unknown unicast packets when a specified traffic level is exceeded, thus preventing packets from proliferating and degrading the LAN.

Note: this issue does not affect EX2200, EX3300, EX4200, and EX9200 Series.

This issue affects Juniper Networks Junos OS on EX Series and QFX5K Series:

15.1 versions prior to 15.1R7-S7;

16.1 versions prior to 16.1R7-S8;

17.2 versions prior to 17.2R3-S4;

17.3 versions prior to 17.3R3-S8;

17.4 versions prior to 17.4R2-S11, 17.4R3-S2;

18.1 versions prior to 18.1R3-S10;

18.2 versions prior to 18.2R3-S5;

18.3 versions prior to 18.3R2-S4, 18.3R3-S2;

18.4 versions prior to 18.4R2-S5, 18.4R3-S3;

19.1 versions prior to 19.1R2-S2, 19.1R3-S2;

19.2 versions prior to 19.2R1-S5, 19.2R2-S1, 19.2R3;

19.3 versions prior to 19.3R2-S4, 19.3R3;

19.4 versions prior to 19.4R1-S3, 19.4R2-S1, 19.4R3;

20.1 versions prior to 20.1R1-S2, 20.1R2.

This issue affects device with RTG configured:

[switch-options redundant-trunk-group]

in combination with the Storm Control configuration:

For Enhanced Layer 2 Software (ELS) release;

[interfaces <interface-name> unit 0 family ethernet-switching storm-control <profile-name>]

(see for reference)

For non-ELS release:

[ethernet-switching-options storm-control interface <RGT_interface>]


[ethernet-switching-options storm-control interface all]


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-2021-0203.


The following software releases have been updated to resolve this specific issue Junos OS: 15.1R7-S7, 16.1R7-S8, 17.2R3-S4, 17.3R3-S8, 17.4R2-S11, 17.4R3-S2, 18.1R3-S10, 18.2R3-S5, 18.3R2-S4, 18.3R3-S2, 18.4R2-S5, 18.4R3-S3, 19.1R2-S2, 19.1R3-S2, 19.2R1-S5, 19.2R2-S1, 19.2R3, 19.3R2-S4, 19.3R3, 19.4R1-S3, 19.4R2-S1, 19.4R3, 20.1R1-S2, 20.1R2, 20.2R1 and all subsequent releases.

This issue is being tracked as 1491669.


There are no known workarounds for this issue.

Software releases or updates are available for download at
Modification History:
2021-01-13: Initial Publication.
CVSS Score:
8.6 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/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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