CVE-2021-0290

high-risk
Published 2021-07-15

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.

Do I need to act?

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0.08% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
6
CVSS 6.5/10 Medium
ADJACENT_NETWORK / LOW complexity

Affected Vendors

References (2)

54
/ 100
high-risk
Severity 21/34 · High
Exploitability 0/34 · Minimal
Exposure 33/34 · Critical