CVE-2021-0203
HIGHDescription
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.
How to fix
No published remediation has been found for this vulnerability's affected products yet.
Mitigation guidance may be in the linked vendor advisories in the References section below.
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CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Exploit Intelligence
Moderate risk: more likely to be exploited than 60% of all known CVEs.
References
Related Vulnerabilities
Other CWE-794 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2026-21876 | Critical | 9.3 | 13% | - | Fix |
| CVE-2019-0002 | Critical | 9.8 | 2.4% | - | - |
| CVE-2020-1665 | Medium | 5.3 | 1.3% | - | - |
| CVE-2021-0233 | High | 7.5 | 1.0% | - | - |
Common questions
How do I fix CVE-2021-0203?
No published fix for CVE-2021-0203 has been found yet. Check the linked vendor advisories for guidance as it becomes available.
Is CVE-2021-0203 being actively exploited?
Not that we know of. CVE-2021-0203 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 1.0% is the estimated probability that it will be exploited in the next 30 days. That is higher than 60% of all scored CVEs.
How severe is CVE-2021-0203?
CVE-2021-0203 has a CVSS v3 base score of 8.6, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.