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

Summary

CVECVE-2026-57029
StatePUBLISHED
Assignerjuniper
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-09 22:17:08 UTC
Updated2026-07-10 17:49:57 UTC
DescriptionA 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.

Risk And Classification

Primary CVSS: v4.0 6 MEDIUM from [email protected]

CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:M/U:X

Problem Types: CWE-820 | CWE-820 CWE-820 Missing Synchronization


VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary6MEDIUMCVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/C...
4.0CNACVSS6MEDIUMCVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/...
3.1[email protected]Secondary5.3MEDIUMCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNACVSS5.3MEDIUMCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v4.0 Breakdown

Attack Vector
Adjacent
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
Low

CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:X/V:X/RE:M/U:X

CVSS v3.1 Breakdown

Attack Vector
Adjacent
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Juniper Networks Junos OS Evolved affected 23.4R2-S7-EVO custom QFX Series
CNA Juniper Networks Junos OS Evolved affected 24.2 24.2R2-S5-EVO custom QFX Series
CNA Juniper Networks Junos OS Evolved affected 24.4 24.4R2-S3-EVO custom QFX Series
CNA Juniper Networks Junos OS Evolved affected 25.2 25.2R2-EVO custom QFX Series

References

ReferenceSourceLinkTags
supportportal.juniper.net/JSA110089 [email protected] supportportal.juniper.net
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

Solutions

CNA: The following software releases have been updated to resolve this specific issue: Junos OS Evolved: 23.4R2-S7-EVO, 24.2R2-S5-EVO, 24.4R2-S3-EVO, 25.2R2-EVO, 25.4R1-EVO, and all subsequent releases.

Workarounds

CNA: There are no known workarounds for this issue.

Exploits

CNA: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

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