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Full vulnerability report · 2020
CVE-2020-1668High confidence

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

Juniper Networks · Junos OS

6.5MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2020-12530

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Fix not verified
01

What, why and how

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.

What

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.

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
an adjacent network → Uncontrolled Resource Consumption → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Adjacent
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-400

CWE-400: Uncontrolled Resource Consumption. The product does not properly control the allocation and maintenance of a limited resource.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVAdjacentAttack vector: The attacker must be on an adjacent or logically close network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
UnauthenticatedCWE-400
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
18.1 < 18.1R3-S11; 18.2 < 18.2R3-S5; 18.3 < 18.3R2-S4, 18.3R3-S3; 18.4 < 18.4R2-S5, 18.4R3-S4; 19.1 < 19.1R3-S2; 19.2 < 19.2R1-S5, 19.2R3; 19.3 < 19.3R2-S4, 19.3R3; 19.4 < 19.4R1-S3, 19.4R2-S1, 19.4R3
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 16 Oct 2020 · Last source change 16 Sept 2024, 18:18 UTC · CWE-400 · Uncontrolled Resource Consumption

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2020-12530
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2020-1668 · cve.blacktree.nl