Vulnerability Database

346,508

Total vulnerabilities in the database

CVE-2021-0290 — juniper / junos

Improper Handling of Exceptional Conditions

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.

  • Published: Jul 15, 2021
  • Updated: Nov 16, 2025
  • CVE: CVE-2021-0290
  • Severity: Medium
  • Exploit:

CVSS v3:

  • Severity: Medium
  • Score: 6.5
  • AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v2:

  • Severity: Low
  • Score: 3.3
  • AV:A/AC:L/Au:N/C:N/I:N/A:P

CWEs:

Software From Fixed in
juniper / junos 16.1-r1 16.1-r1.x
juniper / junos 16.1-r4-s4 16.1-r4-s4.x
juniper / junos 16.1-r4 16.1-r4.x
juniper / junos 16.1-r3 16.1-r3.x
juniper / junos 16.1-r5 16.1-r5.x
juniper / junos 16.1-r2 16.1-r2.x
juniper / junos 16.1-r6 16.1-r6.x
juniper / junos 16.1-r5-s4 16.1-r5-s4.x
juniper / junos 16.1-r6-s1 16.1-r6-s1.x
juniper / junos 16.1-r7 16.1-r7.x
juniper / junos 16.1-r4-s9 16.1-r4-s9.x
juniper / junos 16.1-r6-s3 16.1-r6-s3.x
juniper / junos 16.1-r4-s8 16.1-r4-s8.x
juniper / junos 16.1-r6-s4 16.1-r6-s4.x
juniper / junos 16.1-r6-s6 16.1-r6-s6.x
juniper / junos 16.1-r3-s8 16.1-r3-s8.x
juniper / junos 16.1-r3-s10 16.1-r3-s10.x
juniper / junos 16.1-r4-s3 16.1-r4-s3.x
juniper / junos 16.1 16.1.x
juniper / junos 16.1-r3-s11 16.1-r3-s11.x
juniper / junos 16.1-r7-s3 16.1-r7-s3.x
juniper / junos 16.1-r7-s4 16.1-r7-s4.x
juniper / junos 16.1-r7-s2 16.1-r7-s2.x
juniper / junos 16.1-r7-s5 16.1-r7-s5.x
juniper / junos 16.1-r4-s12 16.1-r4-s12.x
juniper / junos 16.1-r4-s6 16.1-r4-s6.x
juniper / junos 16.1-r4-s2 16.1-r4-s2.x
juniper / junos 16.1-r7-s6 16.1-r7-s6.x
juniper / junos 17.1-r2-s11 17.1-r2-s11.x
juniper / junos 17.1-r3-s1 17.1-r3-s1.x
juniper / junos 17.1-r3-s2 17.1-r3-s2.x
juniper / junos 17.1-r2-s8 17.1-r2-s8.x
juniper / junos 17.1-r2-s9 17.1-r2-s9.x
juniper / junos 17.1-r3 17.1-r3.x
juniper / junos 17.1-r2-s10 17.1-r2-s10.x
juniper / junos 17.1-r2 17.1-r2.x
juniper / junos 17.1-r2-s1 17.1-r2-s1.x
juniper / junos 17.1-r2-s2 17.1-r2-s2.x
juniper / junos 17.1-r2-s3 17.1-r2-s3.x
juniper / junos 17.1-r2-s4 17.1-r2-s4.x
juniper / junos 17.1-r2-s5 17.1-r2-s5.x
juniper / junos 17.1-r2-s6 17.1-r2-s6.x
juniper / junos 17.1-r1-s7 17.1-r1-s7.x
juniper / junos 17.1-r2-s7 17.1-r2-s7.x
juniper / junos 17.1-r1 17.1-r1.x
juniper / junos 17.3-r1 17.3-r1.x
juniper / junos 17.3-r2 17.3-r2.x
juniper / junos 17.3-r2-s2 17.3-r2-s2.x
juniper / junos 17.3-r3 17.3-r3.x
juniper / junos 17.3-r1-s4 17.3-r1-s4.x
juniper / junos 17.3-r3-s1 17.3-r3-s1.x
juniper / junos 17.3-r3-s2 17.3-r3-s2.x
juniper / junos 17.3-r2-s1 17.3-r2-s1.x
juniper / junos 17.3 17.3.x
juniper / junos 17.3-r3-s3 17.3-r3-s3.x
juniper / junos 17.3-r3-s4 17.3-r3-s4.x
juniper / junos 17.3-r3-s5 17.3-r3-s5.x
juniper / junos 17.3-r3-s6 17.3-r3-s6.x
juniper / junos 17.3-r2-s3 17.3-r2-s3.x
juniper / junos 17.3-r1-s1 17.3-r1-s1.x
juniper / junos 17.3-r2-s4 17.3-r2-s4.x
juniper / junos 17.3-r3-s7 17.3-r3-s7.x
juniper / junos 17.3-r2-s5 17.3-r2-s5.x
juniper / junos 17.3-r3-s10 17.3-r3-s10.x
juniper / junos 17.3-r3-s11 17.3-r3-s11.x
juniper / junos 17.4-r1 17.4-r1.x
juniper / junos 17.4-r2 17.4-r2.x
juniper / junos 17.4-r1-s3 17.4-r1-s3.x
juniper / junos 17.4-r2-s2 17.4-r2-s2.x
juniper / junos 17.4-r1-s1 17.4-r1-s1.x
juniper / junos 17.4-r1-s2 17.4-r1-s2.x
juniper / junos 17.4-r3 17.4-r3.x
juniper / junos 17.4-r2-s1 17.4-r2-s1.x
juniper / junos 17.4 17.4.x
juniper / junos 17.4-r1-s5 17.4-r1-s5.x
juniper / junos 17.4-r1-s7 17.4-r1-s7.x
juniper / junos 17.4-r1-s4 17.4-r1-s4.x
juniper / junos 17.4-r2-s3 17.4-r2-s3.x
juniper / junos 17.4-r2-s4 17.4-r2-s4.x
juniper / junos 17.4-r1-s6 17.4-r1-s6.x
juniper / junos 17.4-r2-s5 17.4-r2-s5.x
juniper / junos 17.4-r2-s6 17.4-r2-s6.x
juniper / junos 17.4-r2-s7 17.4-r2-s7.x
juniper / junos 17.4-r2-s8 17.4-r2-s8.x
juniper / junos 17.4-r2-s9 17.4-r2-s9.x
juniper / junos 17.4-r2-s10 17.4-r2-s10.x
juniper / junos 18.1-r1 18.1-r1.x
juniper / junos 18.1-r3 18.1-r3.x
juniper / junos 18.1-r2 18.1-r2.x
juniper / junos 18.1-r3-s4 18.1-r3-s4.x
juniper / junos 18.1-r3-s3 18.1-r3-s3.x
juniper / junos 18.1-r3-s2 18.1-r3-s2.x
juniper / junos 18.1 18.1.x
juniper / junos 18.1-r2-s1 18.1-r2-s1.x
juniper / junos 18.1-r2-s4 18.1-r2-s4.x
juniper / junos 18.1-r2-s2 18.1-r2-s2.x
juniper / junos 18.1-r3-s1 18.1-r3-s1.x
juniper / junos 18.1-r3-s5 18.1-r3-s5.x
juniper / junos 18.1-r3-s6 18.1-r3-s6.x
juniper / junos 18.1-r3-s7 18.1-r3-s7.x
juniper / junos 18.1-r3-s8 18.1-r3-s8.x
juniper / junos 18.1-r3-s9 18.1-r3-s9.x
juniper / junos 18.2-r3-s2 18.2-r3-s2.x
juniper / junos 18.2-r2-s7 18.2-r2-s7.x
juniper / junos 18.2-r1-s2 18.2-r1-s2.x
juniper / junos 18.2-r2-s5 18.2-r2-s5.x
juniper / junos 18.2-r2-s6 18.2-r2-s6.x
juniper / junos 18.2-r3-s1 18.2-r3-s1.x
juniper / junos 18.2-r3 18.2-r3.x
juniper / junos 18.2-r2-s3 18.2-r2-s3.x
juniper / junos 18.2-r2-s4 18.2-r2-s4.x
juniper / junos 18.2-r1-s4 18.2-r1-s4.x
juniper / junos 18.2-r1-s5 18.2-r1-s5.x
juniper / junos 18.2-r2 18.2-r2.x
juniper / junos 18.2-r1 18.2-r1.x
juniper / junos 18.2 18.2.x
juniper / junos 18.2-r2-s1 18.2-r2-s1.x
juniper / junos 18.2-r2-s2 18.2-r2-s2.x
juniper / junos 18.2-r1-s3 18.2-r1-s3.x
juniper / junos 18.3-r1-s1 18.3-r1-s1.x
juniper / junos 18.3-r2 18.3-r2.x
juniper / junos 18.3-r1 18.3-r1.x
juniper / junos 18.3-r1-s2 18.3-r1-s2.x
juniper / junos 18.3 18.3.x
juniper / junos 18.3-r1-s4 18.3-r1-s4.x
juniper / junos 18.3-r1-s3 18.3-r1-s3.x
juniper / junos 18.3-r1-s5 18.3-r1-s5.x
juniper / junos 18.3-r2-s1 18.3-r2-s1.x
juniper / junos 18.3-r2-s2 18.3-r2-s2.x
juniper / junos 18.3-r2-s3 18.3-r2-s3.x
juniper / junos 18.3-r2-s4 18.3-r2-s4.x
juniper / junos 18.3-r3 18.3-r3.x
juniper / junos 18.3-r1-s6 18.3-r1-s6.x
juniper / junos 18.4-r2-s2 18.4-r2-s2.x
juniper / junos 18.4-r1-s6 18.4-r1-s6.x
juniper / junos 18.4-r1-s7 18.4-r1-s7.x
juniper / junos 18.4-r2-s1 18.4-r2-s1.x
juniper / junos 18.4-r2 18.4-r2.x
juniper / junos 18.4-r1-s5 18.4-r1-s5.x
juniper / junos 18.4-r1-s1 18.4-r1-s1.x
juniper / junos 18.4-r1 18.4-r1.x
juniper / junos 18.4-r1-s3 18.4-r1-s3.x
juniper / junos 18.4-r1-s4 18.4-r1-s4.x
juniper / junos 18.4-r1-s2 18.4-r1-s2.x
juniper / junos 18.4 18.4.x
juniper / junos 19.1-r1 19.1-r1.x
juniper / junos 19.1 19.1.x
juniper / junos 19.1-r1-s1 19.1-r1-s1.x
juniper / junos 19.1-r1-s3 19.1-r1-s3.x
juniper / junos 19.1-r1-s2 19.1-r1-s2.x
juniper / junos 19.1-r1-s5 19.1-r1-s5.x
juniper / junos 19.1-r1-s6 19.1-r1-s6.x
juniper / junos 19.1-r2 19.1-r2.x
juniper / junos 19.1-r1-s4 19.1-r1-s4.x
juniper / junos 19.2-r1-s1 19.2-r1-s1.x
juniper / junos 19.2-r1-s2 19.2-r1-s2.x
juniper / junos 19.2 19.2.x
juniper / junos 19.2-r1 19.2-r1.x
juniper / junos 19.3 19.3.x
juniper / junos 19.3-r1 19.3-r1.x
juniper / junos 19.3-r1-s1 19.3-r1-s1.x

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.