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Vulnerability record · public intelligence
CVE-2021-0280
HIGH

Junos OS: PTX Series, QFX10K Series: Upon receipt of specific packets BFD sessions might flap due to DDoS policer implementation in Packet Forwarding Engine

Published Jul 15, 2021 · Updated Oct 23, 2026

Severity · CVSSHIGH · 7.5
Known exploitationNot listed
EPSS / likelihood0.96%
QFinch risk score10 / 100

Original summary

Normalized public record · Updated Oct 23, 2026

Junos OS: PTX Series, QFX10K Series: Upon receipt of specific packets BFD sessions might flap due to DDoS policer implementation in Packet Forwarding Engine

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

Due to an Improper Initialization vulnerability in Juniper Networks Junos OS on PTX platforms and QFX10K Series with Paradise (PE) chipset-based line cards, ddos-protection configuration changes made from the CLI will not take effect as expected beyond the default DDoS (Distributed Denial of Service) settings in the Packet Forwarding Engine (PFE). This may cause BFD sessions to flap when a high rate of specific packets are received. Flapping of BFD sessions in turn may impact routing protocols and network stability, leading to a Denial of Service (DoS) condition. Continued receipt and processing of this packet will create a sustained Denial of Service (DoS) condition. This issue affects only the following platforms with Paradise (PE) chipset-based line cards: PTX1000, PTX3000 (NextGen), PTX5000, PTX10008, PTX10016 Series and QFX10002 Series. This issue affects: Juniper Networks Junos OS 17.4 versions prior to 17.4R3-S5 on PTX Series, QFX10K Series; 18.2 versions prior to 18.2R3-S8 on PTX Series, QFX10K Series; 18.3 versions prior to 18.3R3-S5 on PTX Series, QFX10K Series; 18.4 versions prior to 18.4R2-S8 on PTX Series, QFX10K Series; 19.1 versions prior to 19.1R3-S5 on PTX Series, QFX10K Series; 19.2 versions prior to 19.2R3-S2 on PTX Series, QFX10K Series; 19.3 versions prior to 19.3R3-S2 on PTX Series, QFX10K Series; 19.4 versions prior to 19.4R3-S2 on PTX Series, QFX10K Series; 20.1 versions prior to 20.1R3 on PTX Series, QFX10K Series; 20.2 versions prior to 20.2R2-S3, 20.2R3 on PTX Series, QFX10K Series; 20.3 versions prior to 20.3R2 on PTX Series, QFX10K Series; 20.4 versions prior to 20.4R2 on PTX Series, QFX10K Series.

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

CVENVDEPSS
SSVC priority
MEDIUM
Confidence
10%
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. kb.juniper.net ↗

Record history

Published Jul 15, 2021 · Last refreshed Oct 23, 2026