DoS via Missing Sync in Junos OS Evolved QFX sFlow Collector
CVE-2026-57029 Published on July 9, 2026

Junos OS Evolved: QFX Series: When sFlow collector reachability changes evo-pfemand process can crash
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.

Vendor Advisory NVD

Vulnerability Analysis

Attack Vector:
ADJACENT_NETWORK
Attack Complexity:
HIGH
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
HIGH

Weakness Type

Missing Synchronization

The software utilizes a shared resource in a concurrent manner but does not attempt to synchronize access to the resource. If access to a shared resource is not synchronized, then the resource may not be in a state that is expected by the software. This might lead to unexpected or insecure behaviors, especially if an attacker can influence the shared resource.


Products Associated with CVE-2026-57029

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Juniper Networks Junos Os Evolved
 

Affected Versions

Juniper Networks Junos OS Evolved: