CVE-2026-57030

MEDIUM
Published Jul 9, 2026 Modified Jul 13, 2026 CWE-362

Description

A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). As part of the stateful traffic processing on SRX Series devices flows are being established, and removed when not needed anymore. During the removal process the timeout of a flow should be set to 3 seconds and consequentially the flow should be removed shortly after. Due to a race condition occurring when setting the timeout there is a chance (the exact conditions are outside the attackers control) that the timeout is instead set to a very high value of larger than 10,000 seconds: user@host> show security flow session | match timeout Session ID: 98784248524, Policy name: PROD-FLOW/4, HA State: Active, Timeout: 85250, Session State: Valid This will lead to an accumulation of flows which can be observed by an ever-increasing value of invalidated sessions in the output of 'show security flow session summary': user@host> show security flow session summary | match invalid Invalidated sessions: 216931These sessions can't be cleared manually with the 'clear security flow session' command, which will either lead to forwarding to stop (and the system needs to be manually recovered with a reboot) or to a flowd core and automatic reboot. This issue affects Junos OS on SRX Series: * 24.2 versions before 24.2R2-S3, * 24.4 versions before 24.4R2-S1, 24.4R2-S2, * 25.2 versions before 25.2R1-S2, 25.2R2. This issue does not affect releases earlier than 24.2R1;

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CVSS v3.1 Score

5.9
MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0038
Probability of exploitation
0.30%
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-362 CWE-362

Affected Products

Vendor Product
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper srx1500
juniper srx1600
juniper srx2300
juniper srx300
juniper srx320
juniper srx340
juniper srx345
juniper srx380
juniper srx400
juniper srx4100
juniper srx4120
juniper srx4200
juniper srx4300
juniper srx440
juniper srx4600
juniper srx4700
juniper srx5400
juniper srx5600
juniper srx5800

References

Frequently Asked Questions

What is CVE-2026-57030? +
A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). As part of the stateful traffic processing on SRX Series devices flows are being established, and removed when not needed anymore. During the removal process the timeout of a flow should be set to 3 seconds and consequentially the flow should be removed shortly after. Due to a race condition occurring when setting the timeout there is a chance (the exact conditions are outside the attackers control) that the timeout is instead set to a very high value of larger than 10,000 seconds: user@host> show security flow session | match timeout Session ID: 98784248524, Policy name: PROD-FLOW/4, HA State: Active, Timeout: 85250, Session State: Valid This will lead to an accumulation of flows which can be observed by an ever-increasing value of invalidated sessions in the output of 'show security flow session summary': user@host> show security flow session summary | match invalid Invalidated sessions: 216931These sessions can't be cleared manually with the 'clear security flow session' command, which will either lead to forwarding to stop (and the system needs to be manually recovered with a reboot) or to a flowd core and automatic reboot. This issue affects Junos OS on SRX Series: * 24.2 versions before 24.2R2-S3, * 24.4 versions before 24.4R2-S1, 24.4R2-S2, * 25.2 versions before 25.2R1-S2, 25.2R2. This issue does not affect releases earlier than 24.2R1; It has a CVSS v3.1 base score of 5.9 (MEDIUM).
How severe is CVE-2026-57030? +
CVE-2026-57030 has a CVSS v3.1 score of 5.9 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance. The EPSS score is 0.0038, placing it in the 0th percentile for exploitation probability.
What products are affected by CVE-2026-57030? +
CVE-2026-57030 affects products from juniper, specifically: junos, srx1500, srx1600, srx2300, srx300, srx320, srx340, srx345, srx380, srx400, srx4100, srx4120, srx4200, srx4300, srx440, srx4600, srx4700, srx5400, srx5600, srx5800. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2026-57030? +
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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