{"id":"CVE-2026-57030","aliases":["EUVD-2026-42719","GHSA-6hx5-3rjf-rm36"],"status":"published","title":"Junos OS: SRX Series: Flow sessions are not getting cleared leading to a DoS","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).\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\u003e 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\u003e 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;","severity":{"version":"4.0","score":8.2,"vector":"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00381,"percentile":0.32535,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-362"],"published":"2026-07-09T21:13:12Z","modified":"2026-10-25T15:10:00Z","products":[{"vendor":"juniper","product":"junos"},{"vendor":"juniper networks","product":"junos os"}],"references":[{"url":"https://supportportal.juniper.net/JSA110090","tags":["vendor-advisory","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-57030"},{"url":"https://github.com/advisories/GHSA-6hx5-3rjf-rm36"}],"sources":{"cve":[{"id":"CVE-2026-57030","title":"Junos OS: SRX Series: Flow sessions are not getting cleared leading to a DoS","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).\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\u003e 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\u003e 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;","status":"published","published":"2026-07-09T21:13:12.671Z","modified":"2026-07-10T14:43:39.183Z","cvss":[{"version":"4.0","score":8.2,"vector":"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","level":"high","assessor":"cna"},{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-362"],"updated_at":"2026-11-02T13:43:44.898272Z"}],"euvd":[{"id":"EUVD-2026-42719","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).\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\u003e 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\u003e 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;","status":"published","published":"2026-07-09T21:13:12Z","modified":"2026-07-10T14:43:39Z","cvss":[{"version":"4.0","score":8.2,"vector":"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","level":"high"}],"updated_at":"2026-11-02T18:20:03.345658Z"}],"ghsa":[{"id":"GHSA-6hx5-3rjf-rm36","title":"A Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')...","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).\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\u003e 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\u003e 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;","status":"published","published":"2026-07-10T00:31:26Z","modified":"2026-07-10T00:31:33Z","cvss":[{"version":"4.0","score":8.2,"vector":"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","level":"high"},{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-362"],"updated_at":"2026-11-02T15:09:22.722529Z"}],"nvd":[{"id":"CVE-2026-57030","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).\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\u003e 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\u003e 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;","status":"published","published":"2026-07-09T22:17:08.643Z","modified":"2026-10-25T15:10:00.147Z","cvss":[{"version":"4.0","score":8.2,"vector":"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","level":"high","assessor":"secondary"},{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"}],"cwes":["CWE-362"],"updated_at":"2026-11-02T14:12:28.4135Z"}]}}