CVE-2026-57029

Traffic-forwarding outage via unsynchronized next-hop update

Published Jul 9, 2026 · Updated Jul 9, 2026

Missing synchronization in Junos OS Evolved on QFX Series allows attackers to crash traffic forwarding via sFlow collector changes. The flow collector handler updates a next-hop entry while the sFlow thread reads the same data without synchronization, crashing evo-pfemand. At least one sFlow collector must be configured; attackers need adjacent network access without authentication, cannot control the race timing, and interrupt all forwarding until evo-pfemand restarts automatically.

CVSS severity6.0
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing synchronization in Junos OS Evolved on QFX Series allows attackers to crash traffic forwarding via sFlow collector changes. The flow collector handler updates a next-hop entry while the sFlow thread reads the same data without synchronization, crashing evo-pfemand. At least one sFlow collector must be configured; attackers need adjacent network access without authentication, cannot control the race timing, and interrupt all forwarding until evo-pfemand restarts automatically.

The record

CVE
CVE-2026-57029
Published
Jul 9, 2026
Updated
Jul 9, 2026
Vendor
Juniper Networks
Product
Junos OS Evolved
Classifications
CWE-820, T1499
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 <23.4R2-S7-EVO
  2. Affected versionversion=24.2 <24.2R2-S5-EVO
  3. Affected versionversion=24.4 <24.4R2-S3-EVO
  4. Affected versionversion=25.2 <25.2R2-EVO

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OS Evolvedversion=0 <23.4R2-S7-EVO; version=24.2 <24.2R2-S5-EVO; version=24.4 <24.4R2-S3-EVO; version=25.2 <25.2R2-EVO

Published CVSS scores

5.3Juniper NetworksCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
6.0Juniper NetworksCVSS:4.0/AV:A/AC:L/AT:P/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-820Missing Synchronization
T1499Endpoint Denial of Service

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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