Vulnerability · Published Jul 9, 2026 · Assigned by juniper

CVE-2026-57029Junos OS Evolved: QFX Series: When sFlow collector reachability changes evo-pfemand process can crash

Medium 5.3

In plain English

A medium-severity security flaw in Junos OS Evolved from Juniper Networks. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 9% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.2%top 91.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
Juniper Networks	Junos OS Evolved	0 – before 23.4R2-S7-EVO24.2 – before 24.2R2-S5-EVO24.4 – before 24.4R2-S3-EVO25.2 – before 25.2R2-EVO

Weakness: CWE-820 · Vector: CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://supportportal.juniper.net/JSA110089 vendor-advisory