CVE-2026-57029

MEDIUM
Published Jul 9, 2026 Modified Jul 13, 2026 CWE-820

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.

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CVSS v3.1 Score

5.3
MEDIUM
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0019
Probability of exploitation
0.09%
Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-820 CWE-820

Affected Products

Vendor Product
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper junos_os_evolved
juniper qfx10008
juniper qfx10016
juniper qfx5110
juniper qfx5120
juniper qfx5130
juniper qfx5140
juniper qfx5200
juniper qfx5210
juniper qfx5220
juniper qfx5230-64cd
juniper qfx5240
juniper qfx5241
juniper qfx5250
juniper qfx5700

References

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. It has a CVSS v3.1 base score of 5.3 (MEDIUM).
How severe is CVE-2026-57029? +
CVE-2026-57029 has a CVSS v3.1 score of 5.3 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0019, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-57029? +
CVE-2026-57029 affects products from juniper, specifically: junos_os_evolved, qfx10008, qfx10016, qfx5110, qfx5120, qfx5130, qfx5140, qfx5200, qfx5210, qfx5220, qfx5230-64cd, qfx5240, qfx5241, qfx5250, qfx5700. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-57029? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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