Junos OS: EX2300 Series: High CPU load due to receipt of specific multicast packets on layer 2 interface

Description

On Juniper Networks EX2300 Series, receipt of a stream of specific multicast packets by the layer2 interface can cause high CPU load, which could lead to traffic interruption. This issue occurs when multicast packets are received by the layer 2 interface. To check if the device has high CPU load due to this issue, the administrator can issue the following command: user@host> show chassis routing-engine Routing Engine status: ... Idle 2 percent the "Idle" value shows as low (2 % in the example above), and also the following command: user@host> show system processes summary ... PID USERNAME PRI NICE SIZE RES STATE TIME WCPU COMMAND 11639 root 52 0 283M 11296K select 12:15 44.97% eventd 11803 root 81 0 719M 239M RUN 251:12 31.98% fxpc{fxpc} the eventd and the fxpc processes might use higher WCPU percentage (respectively 44.97% and 31.98% in the above example). This issue affects Juniper Networks Junos OS on EX2300 Series: 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-S2, 20.1R2.

Scores

EPSS (exploitation in 30 days)

0.51% · top 56% of all CVEs (7 Nov 2026)

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

Weakness

• CWE-400 Uncontrolled Resource Consumption (opens in a new tab)All about CWE-400 and its CVEs

Affected products

• Juniper Networks · Junos OS

  • 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-S2, 20.1R2

What to do

Solution: The following software releases have been updated to resolve this specific issue: Junos OS 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-S2, 20.1R2, 20.2R1, and all subsequent releases.

Workaround: There are no available workarounds for this issue.

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

References (1)

• https://kb.juniper.net/JSA11065 (opens in a new tab)x_refsource_CONFIRMx_transferred

Sources

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

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2020-1668](https://trackcve.app/badge/CVE-2020-1668.svg)](https://trackcve.app/cve/CVE-2020-1668)

Record last updated 16 Sept 2024, 18:18 UTC.