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CVE-2020-1689

Junos OS: EX4300-MP/EX4600/QFX5K Series: High CPU load due to receipt of specific layer 2 frames when deployed in a Virtual Chassis configuration

Medium6.5EPSS 0.50%
Published
Updated
Reserved
Assigned by
juniper

Description

On Juniper Networks EX4300-MP Series, EX4600 Series and QFX5K Series deployed in a Virtual Chassis configuration, receipt of a stream of specific layer 2 frames can cause high CPU load, which could lead to traffic interruption. This issue does not occur when the device is deployed in Stand Alone configuration. The offending layer 2 frame packets can originate only from within the broadcast domain where the device is connected. This issue affects Juniper Networks Junos OS on EX4300-MP Series, EX4600 Series and QFX5K Series: 17.3 versions prior to 17.3R3-S9; 17.4 versions prior to 17.4R2-S11, 17.4R3-S2, 17.4R3-S3; 18.1 versions prior to 18.1R3-S11; 18.2 versions prior to 18.2R3-S5; 18.3 versions prior to 18.3R2-S4, 18.3R3-S3; 18.4 versions prior to 18.4R2-S5, 18.4R3-S4; 19.1 versions prior to 19.1R3-S2; 19.2 versions prior to 19.2R1-S5, 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-S3, 20.1R2.

Scores

CVSS scores of CVE-2020-1689, by who scored it
Scored byCVSSScoreVector
juniperCNA (assigner)3.1Medium6.5CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVDNVD · Modified3.1Medium6.5CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS (exploitation in 30 days)
0.50% · top 57% of all CVEs (6 Nov 2026)
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.5.

Weakness

Affected products

  • Juniper Networks · Junos OS

    • affected 17.3 – < 17.3R3-S9
    • affected 17.4 – < 17.4R2-S11, 17.4R3-S2, 17.4R3-S3
    • affected 18.1 – < 18.1R3-S11
    • affected 18.2 – < 18.2R3-S5
    • affected 18.3 – < 18.3R2-S4, 18.3R3-S3
    • affected 18.4 – < 18.4R2-S5, 18.4R3-S4
    • affected 19.1 – < 19.1R3-S2
    • affected 19.2 – < 19.2R1-S5, 19.2R3
    • affected 19.3 – < 19.3R2-S4, 19.3R3
    • affected 19.4 – < 19.4R1-S3, 19.4R2-S1, 19.4R3
    • affected 20.1 – < 20.1R1-S3, 20.1R2

What to do

Solution: The following software releases have been updated to resolve this specific issue: Junos OS 17.3R3-S9, 17.4R2-S11, 17.4R3-S2, 17.4R3-S3, 18.1R3-S11, 18.2R3-S5, 18.3R2-S4, 18.3R3-S3, 18.4R2-S5, 18.4R3-S4, 19.1R3-S2, 19.2R1-S5, 19.2R3, 19.3R2-S4, 19.3R3, 19.4R1-S3, 19.4R2-S1, 19.4R3, 20.1R1-S3, 20.1R2, 20.2R1, and all subsequent releases.

Workaround: There are no viable workarounds for this issue.

Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

References (1)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .