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CVE-2020-1670

Junos OS: EX4300 Series: High CPU load due to receipt of specific IPv4 packets

Medium6.5EPSS 0.53%
Published
Updated
Reserved
Assigned by
juniper

Description

On Juniper Networks EX4300 Series, receipt of a stream of specific IPv4 packets can cause Routing Engine (RE) high CPU load, which could lead to network protocol operation issue and traffic interruption. This specific packets can originate only from within the broadcast domain where the device is connected. This issue occurs when the packets enter to the IRB interface. Only IPv4 packets can trigger this issue. IPv6 packets cannot trigger this issue. This issue affects Juniper Networks Junos OS on EX4300 series: 17.3 versions prior to 17.3R3-S9; 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-S4; 18.3 versions prior to 18.3R2-S4, 18.3R3-S2; 18.4 versions prior to 18.4R2-S4, 18.4R3-S2; 19.1 versions prior to 19.1R2-S2, 19.1R3-S1; 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; 20.1 versions prior to 20.1R1-S3, 20.1R2.

Scores

CVSS scores of CVE-2020-1670, 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)
0.53% · top 55% 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
    • affected 18.1 – < 18.1R3-S10
    • affected 18.2 – < 18.2R3-S4
    • affected 18.3 – < 18.3R2-S4, 18.3R3-S2
    • affected 18.4 – < 18.4R2-S4, 18.4R3-S2
    • affected 19.1 – < 19.1R2-S2, 19.1R3-S1
    • affected 19.2 – < 19.2R1-S5, 19.2R2-S1, 19.2R3
    • affected 19.3 – < 19.3R2-S4, 19.3R3
    • affected 19.4 – < 19.4R1-S3, 19.4R2
    • affected 20.1 – < 20.1R1-S3, 20.1R2

What to do

Solution: The following software releases have been updated to resolve this specific issue: 17.3R3-S9, 17.4R2-S11, 17.4R3-S2, 18.1R3-S10, 18.2R3-S4, 18.3R2-S4, 18.3R3-S2, 18.4R2-S4, 18.4R3-S2, 19.1R2-S2, 19.1R3-S1, 19.2R1-S5, 19.2R2-S1, 19.2R3, 19.3R2-S4, 19.3R3, 19.4R1-S3, 19.4R2, 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 .