{"id":"CVE-2024-39542","url":"https://www.cyber-defence.io/tools/cve/CVE-2024-39542","generatedAt":"2026-10-28T08:11:26.930Z","title":"An Improper Validation of Syntactic Correctness of Input vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series with MPC10/11 or LC9600, MX304, and Junos OS Evolved on ACX Series and PTX Series allows an…","description":"An Improper Validation of Syntactic Correctness of Input vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series with MPC10/11 or LC9600, MX304, and Junos OS Evolved on ACX Series and PTX Series allows an unauthenticated, network based attacker to cause a Denial-of-Service (DoS).\n\nThis issue can occur in two scenarios:\n\n1. If a device, which is configured with SFLOW and ECMP, receives specific valid transit traffic, which is subject to sampling, the packetio process crashes, which in turn leads to an evo-aftman crash and causes the FPC to stop working until it is restarted. (This scenario is only applicable to PTX but not to ACX or MX.)\n\n2. If a device receives a malformed CFM packet on an interface configured with CFM, the packetio process crashes, which in turn leads to an evo-aftman crash and causes the FPC to stop working until it is restarted. Please note that the CVSS score is for the formally more severe issue 1.\n\nThe CVSS score for scenario 2. is: 6.5 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)\n\n\n\n\nThis issue affects Junos OS:\n\n\n\n  *  All versions before 21.2R3-S4,\n  *  21.4 versions before 21.4R2,\n  *  22.2 versions before 22.2R3-S2; \n\n\n\n\nJunos OS Evolved:\n\n\n\n\n  *  All versions before 21.2R3-S8-EVO,\n  *  21.4 versions before 21.4R2-EVO.","published":"2024-07-11T17:15:13.000Z","lastModified":"2026-06-17T07:42:10.000Z","status":"Analyzed","sourceIdentifier":"sirt@juniper.net","cvss":{"version":"4.0","score":8.7,"severity":"HIGH","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/M"},"cwe":["CWE-1286"],"affected":["juniper/junos","juniper/junos os evolved"],"epss":{"score":0.00473,"percentile":0.40686,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.47%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://supportportal.juniper.net/JSA83002","tags":["Vendor Advisory"],"source":"sirt@juniper.net"},{"url":"https://supportportal.juniper.net/JSA83002","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2024-39542","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}