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2021-07 Security Bulletin: Junos OS: MX Series, EX9200 Series, SRX4600: Ethernet interface vulnerable to specially crafted frames (CVE-2021-0290)



Article ID: JSA11192 SECURITY_ADVISORIES Last Updated: 14 Jul 2021Version: 2.0
Product Affected:
This issue affects Junos OS 16.1, 17.1, 17.2, 17.3, 17.4, 18.1, 18.2, 18.3, 18.4, 19.1, 19.2, 19.3. Affected platforms: EX9200 Series, MX Series, SRX4600.

Improper Handling of Exceptional Conditions in Ethernet interface frame processing of Juniper Networks Junos OS allows an attacker to send specially crafted frames over the local Ethernet segment, causing the interface to go into a down state, resulting in a Denial of Service (DoS) condition. The interface does not recover on its own and the FPC must be reset manually. Continued receipt and processing of these frames will create a sustained Denial of Service (DoS) condition.

This issue is platform-specific and affects the following platforms and line cards:

  • MPC7E/8E/9E and MPC10E on MX240, MX480, MX960, MX2008, MX2010, and MX2020
  • MX204, MX10003, MX10008, MX10016
  • EX9200, EX9251
  • SRX4600

No other products or platforms are affected by this vulnerability.

An indication of this issue occurring can be seen in the system log messages, as shown below:

user@host> show log messages | match "Failed to complete DFE tuning"
fpc4 smic_phy_dfe_tuning_state: et-4/1/6 - Failed to complete DFE tuning (count 3)

and interface will be in a permanently down state:

user@host> show interfaces et-4/1/6 terse
Interface Admin Link Proto Local Remote
et-4/1/6 up down
et-4/1/6.0 up down aenet --> ae101.0

This issue affects Juniper Networks Junos OS:

  • 16.1 versions prior to 16.1R7-S7 on MX Series;
  • 17.1R1 and later versions prior to 17.2R3-S3 on MX Series;
  • 17.3 versions prior to 17.3R3-S8 on MX Series;
  • 17.4 versions prior to 17.4R2-S11, 17.4R3-S1 on MX Series, SRX4600;
  • 18.1 versions prior to 18.1R3-S10 on MX Series, EX9200 Series, SRX4600;
  • 18.2 versions prior to 18.2R3-S3 on MX Series, EX9200 Series, SRX4600;
  • 18.3 versions prior to 18.3R3-S1 on MX Series, EX9200 Series, SRX4600;
  • 18.4 versions prior to 18.4R2-S3, 18.4R3 on MX Series, EX9200 Series, SRX4600;
  • 19.1 versions prior to 19.1R2-S1, 19.1R3 on MX Series, EX9200 Series, SRX4600;
  • 19.2 versions prior to 19.2R1-S3, 19.2R2 on MX Series, EX9200 Series, SRX4600;
  • 19.3 versions prior to 19.3R2 on MX Series, EX9200 Series, SRX4600.

This issue does not affect Juniper Networks Junos OS versions prior to 16.1R1.

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-2021-0290.


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

This issue is being tracked as 1463015.

There are no viable workarounds for this issue.
Software releases or updates are available for download at
Modification History:
2021-07-14: Initial Publication.

CVSS Score:
6.5 (CVSS:3.1/AV:A/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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