CVE-2026-57029

Undergoing Analysis Undergoing Analysis - In Progress

Missing Synchronization DoS in Junos OS Evolved on QFX Series

Publication date: 2026-07-09

Last updated on: 2026-07-10

Assigner: Juniper Networks, Inc.

Description

A Missing Synchronization vulnerability in the flow collector handler of Juniper Networks Junos OS Evolved on QFX Series allows an adjacent, unauthenticated attacker to cause a Denial-of-Service (DoS). When the reachability of an sFlow collector changes, the corresponding next-hop entry is updated. If this update occurs simultaneously with the sFlow thread accessing the next-hop data (which is outside the attackers control), it causes the evo-pfemand process to crash, impacting all traffic forwarding until the automatic process restart has completed. This issue affects Junos OS Evolved on QFX Series: * all 23.2 versions, * 23.4 versions before 23.4R2-S7-EVO, * 24.2 versions before 24.2R2-S5-EVO, * 24.4 versions before 24.4R2-S3-EVO, * 25.2 versions before 25.2R2-EVO.

CVSS Scores

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Meta Information

Published

2026-07-09

Last Modified

2026-07-10

Generated

2026-07-11

AI Q&A

2026-07-10

EPSS Evaluated

N/A

NVD

CVE-2026-57029

EUVD

EUVD-2026-42718

Affected Vendors & Products

Vendor	Product	Version / Range
juniper_networks	junos_os_evolved	23.2
juniper_networks	junos_os_evolved	to 23.4R2-S7-EVO (exc)
juniper_networks	junos_os_evolved	to 24.2R2-S5-EVO (exc)
juniper_networks	junos_os_evolved	to 24.4R2-S3-EVO (exc)
juniper_networks	junos_os_evolved	to 25.2R2-EVO (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-820	The product utilizes a shared resource in a concurrent manner but does not attempt to synchronize access to the resource.

Attack-Flow Graph

Executive Summary

This vulnerability is a Missing Synchronization issue in the flow collector handler of Juniper Networks Junos OS Evolved on QFX Series devices. It allows an adjacent, unauthenticated attacker to cause a Denial-of-Service (DoS) condition.

Specifically, when the reachability of an sFlow collector changes, the system updates the corresponding next-hop entry. If this update happens at the same time as the sFlow thread is accessing the next-hop data, it causes a process called evo-pfemand to crash. This crash disrupts all traffic forwarding until the process automatically restarts.

Impact Analysis

The main impact of this vulnerability is a Denial-of-Service (DoS) condition on affected Juniper QFX Series devices running Junos OS Evolved. An attacker adjacent to the device can trigger a crash of the evo-pfemand process, which handles traffic forwarding.

During the crash and subsequent automatic restart of this process, all traffic forwarding is impacted, potentially causing network outages or degraded network performance.

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