CVE-2026-57020

Network traffic interruption via multicast forwarding loop

Published Jul 9, 2026 · Updated Jul 9, 2026

Denial of service in the Junos OS PFE on QFX10000 Series allows attackers to interrupt network traffic via IPv6 multicast packets. On an EVPN-VXLAN spine, the PFE floods packets arriving on a non-IRB interface to peer spines and ESI leaves, creating an endless forwarding loop that saturates links. Exposure requires such traffic to reach an affected spine running before 23.2R2-S7, 23.4R2-S8, 24.2R2-S4, or 24.4R2-S4.

CVSS severity7.1
High
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Junos OS PFE on QFX10000 Series allows attackers to interrupt network traffic via IPv6 multicast packets. On an EVPN-VXLAN spine, the PFE floods packets arriving on a non-IRB interface to peer spines and ESI leaves, creating an endless forwarding loop that saturates links. Exposure requires such traffic to reach an affected spine running before 23.2R2-S7, 23.4R2-S8, 24.2R2-S4, or 24.4R2-S4.

The record

CVE
CVE-2026-57020
Published
Jul 9, 2026
Updated
Jul 9, 2026
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-754, T1498.001
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <23.2R2-S7
  2. Affected versionversion=23.4 <23.4R2-S8
  3. Affected versionversion=24.2 <24.2R2-S4
  4. Affected versionversion=24.4 <24.4R2-S4

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=0 <23.2R2-S7; version=23.4 <23.4R2-S8; version=24.2 <24.2R2-S4; version=24.4 <24.4R2-S4

Published CVSS scores

6.5Juniper Networks, Inc.CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.1Juniper Networks, Inc.CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-754Improper Check for Unusual or Exceptional Conditions
T1498.001Direct Network Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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