{"id":"CVE-2026-57027","state":"PUBLISHED","title":"Junos OS: EX4100 Series, EX4400: With sFlow configured in a VC scenario multicast traffic leads to an FPC crash","description":"A Missing Release of Memory after Effective Lifetime vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on specific EX Series devices allows an unauthenticated adjacent attacker to cause a Denial-of-Service (DoS).When sFlow is configured in a Virtual Chassis (VC) scenario with EX4100 Series or EX4400 Series devices, multicast traffic which is received on one VC member and sent out on another member leads to a memory leak and ultimately an FPC crash and restart.\n\nThe leak can be monitored by watching the continuous increase of the buffer values in the output of:\n\nuser@host> show chassis fpc \nThis issue affects Junos OS on EX4100 Series and EX4400:\n\n\n  *  all versions before 23.2R2-S7,\n  *  23.4 versions before 23.4R2-S7,\n  *  24.2 versions before 24.2R2-S4,\n  *  24.4 versions before 24.4R2.","publishedAt":"2026-07-09T21:08:07.684Z","updatedAt":"2026-07-10T14:33:33.977Z","severity":{"score":7.1,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:A/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","source":"juniper"},"assigner":"juniper","products":["Juniper Networks Junos OS"],"affected":[{"vendor":"Juniper Networks","product":"Junos OS","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"23.2R2-S7","versionType":"custom"},{"version":"23.4","status":"affected","lessThan":"23.4R2-S7","versionType":"custom"},{"version":"24.2","status":"affected","lessThan":"24.2R2-S4","versionType":"custom"},{"version":"24.4","status":"affected","lessThan":"24.4R2","versionType":"custom"}],"platforms":["EX4100 Series","EX4400 Series"]}],"references":["https://supportportal.juniper.net/JSA110087"],"weaknesses":["CWE-401"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/57xxx/CVE-2026-57027.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-57027","state":"PUBLISHED","datePublished":"2026-07-09T21:08:07.684Z","dateUpdated":"2026-07-10T14:33:33.977Z","assignerShortName":"juniper","assignerOrgId":"8cbe9d5a-a066-4c94-8978-4b15efeae968","dateReserved":"2026-06-23T16:27:00.248Z"},"containers":{"cna":{"title":"Junos OS: EX4100 Series, EX4400: With sFlow configured in a VC scenario multicast traffic leads to an FPC crash","descriptions":[{"lang":"en","value":"A Missing Release of Memory after Effective Lifetime vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on specific EX Series devices allows an unauthenticated adjacent attacker to cause a Denial-of-Service (DoS).When sFlow is configured in a Virtual Chassis (VC) scenario with EX4100 Series or EX4400 Series devices, multicast traffic which is received on one VC member and sent out on another member leads to a memory leak and ultimately an FPC crash and restart.\n\nThe leak can be monitored by watching the continuous increase of the buffer values in the output of:\n\nuser@host> show chassis fpc \nThis issue affects Junos OS on EX4100 Series and EX4400:\n\n\n  *  all versions before 23.2R2-S7,\n  *  23.4 versions before 23.4R2-S7,\n  *  24.2 versions before 24.2R2-S4,\n  *  24.4 versions before 24.4R2."}],"affected":[{"vendor":"Juniper Networks","product":"Junos OS","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"23.2R2-S7","versionType":"custom"},{"version":"23.4","status":"affected","lessThan":"23.4R2-S7","versionType":"custom"},{"version":"24.2","status":"affected","lessThan":"24.2R2-S4","versionType":"custom"},{"version":"24.4","status":"affected","lessThan":"24.4R2","versionType":"custom"}],"platforms":["EX4100 Series","EX4400 Series"]}],"references":[{"url":"https://supportportal.juniper.net/JSA110087","tags":["vendor-advisory"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"ADJACENT_NETWORK","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:A/AC:L/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":"AUTOMATIC","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"ADJACENT","baseScore":7.1,"baseSeverity":"HIGH","privilegesRequired":"NONE","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"CVSS:4.0/AV:A/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","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"MODERATE"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-401","description":"CWE-401 Missing Release of Memory after Effective Lifetime","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"juniper","orgId":"8cbe9d5a-a066-4c94-8978-4b15efeae968","dateUpdated":"2026-07-09T21:08:07.684Z"},"configurations":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"A system is only affected if sFlow for multicast is explicitly enabled with:<br><br><tt>[ forwarding-options sflow egress-multicast enable ]</tt>"}],"value":"A system is only affected if sFlow for multicast is explicitly enabled with:\n\n[ forwarding-options sflow egress-multicast enable ]"}],"datePublic":"2026-07-08T16:00:00.000Z","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."}],"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: 23.2R2-S7, 23.4R2-S7, 24.2R2-S4, 24.4R2, 25.2R1, and all subsequent releases."}],"value":"The following software releases have been updated to resolve this specific issue:\n\nJunos OS: 23.2R2-S7, 23.4R2-S7, 24.2R2-S4, 24.4R2, 25.2R1, and all subsequent releases."}],"source":{"advisory":"JSA110087","defect":["1824592"],"discovery":"USER"},"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":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-07-10T14:33:27.417390Z","id":"CVE-2026-57027","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-07-10T14:33:33.977Z"}}]}}}