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CVE-2026-57029

MEDIUMCVSS 6/10EPSS 0.19%

Last modified

CVE-2026-57029 is a medium-severity vulnerability rated 6/10 on the CVSS scale. 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.. EPSS estimates a 0.19% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1
5.3/10

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

CVSS 4.0
6/10

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

EPSS Probability
0.19%

8.8th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
JuniperJunos Os Evolved23.2
JuniperJunos Os Evolved23.4
JuniperJunos Os Evolved24.2
JuniperJunos Os Evolved24.4
JuniperJunos Os Evolved25.2

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-57029?
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.
How severe is CVE-2026-57029?
CVE-2026-57029 has a CVSS score of 6/10 (MEDIUM severity). The EPSS model estimates a 0.19% probability of exploitation in the next 30 days.
How do I fix CVE-2026-57029?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST