{"id":"CVE-2026-21918","aliases":["EUVD-2026-2697","GHSA-9m47-29xf-m969"],"status":"published","title":"Junos OS: SRX and MX Series: When TCP packets occur in a specific sequence flowd crashes","description":"A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX and MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). On all SRX and MX Series platforms, when during TCP session establishment a specific sequence of packets is encountered a double free happens. This causes flowd to crash and the respective FPC to restart.\n\n\n\n\n\nThis issue affects Junos OS on SRX and MX Series:\n\n\n\n  *  all versions before 22.4R3-S7,\n  *  23.2 versions before 23.2R2-S3,\n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R2.","severity":{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:M","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00407,"percentile":0.35332,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-415"],"published":"2026-01-15T20:27:54Z","modified":"2026-06-17T10:19:09Z","products":[{"vendor":"juniper","product":"junos"},{"vendor":"juniper networks","product":"junos os"}],"references":[{"url":"https://supportportal.juniper.net/JSA106018","tags":["vendor-advisory","Vendor Advisory"]},{"url":"https://kb.juniper.net/JSA106018","tags":["vendor-advisory","Vendor Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-21918"},{"url":"https://github.com/advisories/GHSA-9m47-29xf-m969"}],"sources":{"cve":[{"id":"CVE-2026-21918","title":"Junos OS: SRX and MX Series: When TCP packets occur in a specific sequence flowd crashes","description":"A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX and MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). On all SRX and MX Series platforms, when during TCP session establishment a specific sequence of packets is encountered a double free happens. This causes flowd to crash and the respective FPC to restart.\n\n\n\n\n\nThis issue affects Junos OS on SRX and MX Series:\n\n\n\n  *  all versions before 22.4R3-S7,\n  *  23.2 versions before 23.2R2-S3,\n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R2.","status":"published","published":"2026-01-15T20:27:54.743Z","modified":"2026-01-15T21:13:00.74Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:M","level":"high","assessor":"cna"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-415"],"updated_at":"2026-11-02T13:41:42.05254Z"}],"euvd":[{"id":"EUVD-2026-2697","description":"A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX and MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). On all SRX and MX Series platforms, when during TCP session establishment a specific sequence of packets is encountered a double free happens. This causes flowd to crash and the respective FPC to restart.\n\n\n\n\n\nThis issue affects Junos OS on SRX and MX Series:\n\n\n\n  *  all versions before 22.4R3-S7,\n  *  23.2 versions before 23.2R2-S3,\n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R2.","status":"published","published":"2026-01-15T20:27:54Z","modified":"2026-01-15T21:13:00Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:M","level":"high"}],"updated_at":"2026-11-02T19:48:50.882066Z"}],"ghsa":[{"id":"GHSA-9m47-29xf-m969","title":"A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on...","description":"A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX and MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). On all SRX and MX Series platforms, when during TCP session establishment a specific sequence of packets is encountered a double free happens. This causes flowd to crash and the respective FPC to restart.\n\n\n\n\n\nThis issue affects Junos OS on SRX and MX Series:\n\n\n\n  *  all versions before 22.4R3-S7,\n  *  23.2 versions before 23.2R2-S3,\n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R2.","status":"published","published":"2026-01-15T21:31:48Z","modified":"2026-01-15T21:31:55Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/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:A/V:X/RE:M/U:X","level":"high"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-415"],"updated_at":"2026-11-02T15:05:38.149378Z"}],"nvd":[{"id":"CVE-2026-21918","description":"A Double Free vulnerability in the flow processing daemon (flowd) of Juniper Networks Junos OS on SRX and MX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). On all SRX and MX Series platforms, when during TCP session establishment a specific sequence of packets is encountered a double free happens. This causes flowd to crash and the respective FPC to restart.\n\n\n\n\n\nThis issue affects Junos OS on SRX and MX Series:\n\n\n\n  *  all versions before 22.4R3-S7,\n  *  23.2 versions before 23.2R2-S3,\n  *  23.4 versions before 23.4R2-S4,\n  *  24.2 versions before 24.2R2.","status":"published","published":"2026-01-15T21:16:08.05Z","modified":"2026-06-17T10:19:09.647Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/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:A/V:X/RE:M/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"}],"cwes":["CWE-415"],"updated_at":"2026-11-02T14:12:04.066712Z"}]}}