Junos OS: SRX Series: Flow sessions are not getting cleared leading to a DoS

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Summary

CVECVE-2026-57030
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 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;

Risk And Classification

Primary CVSS: v4.0 8.2 HIGH from [email protected]

CVSS:4.0/AV:N/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:U/V:X/RE:M/U:X

Problem Types: CWE-362 | CWE-362 CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.2HIGHCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/C...
4.0CNACVSS8.2HIGHCVSS:4.0/AV:N/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]Secondary5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNACVSS5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v4.0 Breakdown

Attack Vector
Network
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:N/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:U/V:X/RE:M/U:X

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Juniper Networks Junos OS affected 24.2 24.2R2-S3 custom SRX Series
CNA Juniper Networks Junos OS affected 24.4 24.4R2-S1 custom SRX Series
CNA Juniper Networks Junos OS affected 25.2 25.2R1-S2 custom SRX Series
CNA Juniper Networks Junos OS unaffected 24.2R1 custom SRX Series

References

ReferenceSourceLinkTags
supportportal.juniper.net/JSA110090 [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: 24.2R2-S3, 24.4R2-S1, 25.2R1-S2, 25.2R2, 25.4R1, 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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