These 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:
This issue does not affect releases earlier than 24.2R1;
"}],"value":"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).\n\nAs 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:\n\n\n\nuser@host> show security flow session | match timeout\nSession ID: 98784248524, Policy name: PROD-FLOW/4, HA State: Active, Timeout: 85250, Session State: Valid\n\nThis 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':\n\nuser@host> show security flow session summary | match invalid\nInvalidated 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.\n\n\nThis issue affects Junos OS on SRX Series:\n\n\n * 24.2 versions before 24.2R2-S3,\n * 24.4 versions before 24.4R2-S1, 24.4R2-S2,\n * 25.2 versions before 25.2R1-S2, 25.2R2.\n\n\n\n\nThis issue does not affect releases earlier than 24.2R1;"}],"exploits":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"Juniper SIRT is not aware of any malicious exploitation of this vulnerability."}],"value":"Juniper SIRT is not aware of any malicious exploitation of this vulnerability."}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":5.9,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]},{"cvssV4_0":{"Automatable":"YES","Recovery":"USER","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":8.2,"baseSeverity":"HIGH","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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/AU:Y/R:U/RE:M","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"MODERATE"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-362","description":"CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')","lang":"en","type":"CWE"}]}],"providerMetadata":{"orgId":"8cbe9d5a-a066-4c94-8978-4b15efeae968","shortName":"juniper","dateUpdated":"2026-07-09T21:13:12.671Z"},"references":[{"tags":["vendor-advisory"],"url":"https://supportportal.juniper.net/JSA110090"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"The following software releases have been updated to resolve this specific issue:\n\nJunos OS: 24.2R2-S3, 24.4R2-S1, 25.2R1-S2, 25.2R2, 25.4R1, and all subsequent releases."}],"value":"The following software releases have been updated to resolve this specific issue:\n\nJunos OS: 24.2R2-S3, 24.4R2-S1, 25.2R1-S2, 25.2R2, 25.4R1, and all subsequent releases."}],"source":{"advisory":"JSA110090","defect":["1876709"],"discovery":"USER"},"title":"Junos OS: SRX Series: Flow sessions are not getting cleared leading to a DoS","workarounds":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"There are no known workarounds for this issue."}],"value":"There are no known workarounds for this issue."}],"x_generator":{"engine":"Vulnogram 0.1.0-dev"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-10T14:42:22.610309Z","id":"CVE-2026-57030","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-07-10T14:43:39.183Z"}}]}}