{"id":"CVE-2026-21917","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-21917","generatedAt":"2026-10-28T09:42:18.627Z","title":"An Improper Validation of Syntactic Correctness of Input vulnerability in the Web-Filtering module of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).","description":"An Improper Validation of Syntactic Correctness of Input vulnerability in the Web-Filtering module of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).\n\nIf an SRX device configured for UTM Web-Filtering receives a specifically malformed SSL packet, this will cause an FPC crash and restart.\nThis issue affects Junos OS on SRX Series:\n\n\n\n  *  23.2 versions from 23.2R2-S2 before 23.2R2-S5, \n  *  23.4 versions from 23.4R2-S1 before 23.4R2-S5,\n  *  24.2 versions before 24.2R2-S2,\n  *  24.4 versions before 24.4R1-S3, 24.4R2.\n\n\nEarlier versions of Junos are also affected, but no fix is available.","published":"2026-01-15T21:16:08.000Z","lastModified":"2026-06-17T10:19:09.000Z","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"],"epss":{"score":0.0041,"percentile":0.35105,"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 (0.41%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://kb.juniper.net/JSA105996","tags":["Vendor Advisory"],"source":"sirt@juniper.net"},{"url":"https://supportportal.juniper.net/JSA105996","tags":["Vendor Advisory"],"source":"sirt@juniper.net"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-21917","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."}