CVE-2026-21917

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"462CFD52-D3E2-4F7A-98AC-C589D2420556", "vulnerable": false}, {"criteria": "cpe:2.3:h:juniper:srx5400:-:*:*:*:*:*:*:*", "matchCriteriaId": "2FDDC897-747F-44DD-9599-7266F9B5B7B1", "vulnerable": false}, {"criteria": "cpe:2.3:h:juniper:srx5600:-:*:*:*:*:*:*:*", "matchCriteriaId": "68CA098D-CBE4-4E62-9EC0-43E1B6098710", "vulnerable": false}, {"criteria": "cpe:2.3:h:juniper:srx5800:-:*:*:*:*:*:*:*", "matchCriteriaId": "66F474D4-79B6-4525-983C-9A9011BD958B", "vulnerable": false}], "negate": false, "operator": "OR"}], "operator": "AND"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "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,\u00a0\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."}, {"lang": "es", "value": "Una vulnerabilidad de validaci\u00f3n incorrecta de la correcci\u00f3n sint\u00e1ctica de la entrada en el m\u00f3dulo de filtrado web de Juniper Networks Junos OS en la serie SRX permite a un atacante no autenticado y basado en red causar una denegaci\u00f3n de servicio (DoS).\n\nSi un dispositivo SRX configurado para filtrado web UTM recibe un paquete SSL espec\u00edficamente malformado, esto causar\u00e1 un fallo y reinicio del FPC.\nEste problema afecta a Junos OS en la serie SRX:\n\n * Versiones 23.2 desde 23.2R2-S2 anteriores a 23.2R2-S5,\n * Versiones 23.4 desde 23.4R2-S1 anteriores a 23.4R2-S5,\n * Versiones 24.2 anteriores a 24.2R2-S2,\n * Versiones 24.4 anteriores a 24.4R1-S3, 24.4R2.\n\nLas versiones anteriores de Junos tambi\u00e9n est\u00e1n afectadas, pero no hay una soluci\u00f3n disponible."}], "id": "CVE-2026-21917", "lastModified": "2026-06-17T10:19:09.490", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "sirt@juniper.net", "type": "Secondary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "YES", "Recovery": "AUTOMATIC", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 8.7, "baseSeverity": "HIGH", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "privilegesRequired": "NONE", "providerUrgency": "NOT_DEFINED", "subAvailabilityImpact": "LOW", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "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", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "MODERATE"}, "source": "sirt@juniper.net", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-21917", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-01-15T21:12:30.579909Z", "version": "2.0.3"}}]}, "published": "2026-01-15T21:16:07.877", "references": [{"source": "sirt@juniper.net", "tags": ["Vendor Advisory"], "url": "https://kb.juniper.net/JSA105996"}, {"source": "sirt@juniper.net", "tags": ["Vendor Advisory"], "url": "https://supportportal.juniper.net/JSA105996"}], "sourceIdentifier": "sirt@juniper.net", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-1286"}], "source": "sirt@juniper.net", "type": "Secondary"}]}

{}

{"analysis": {"en": {"generated_at": "2026-04-18T05:56:21.616864+00:00", "value": {"mitigation_remediation": ["Upgrade Junos OS to a patched release such as 23.2R2\u2011S5, 23.4R2\u2011S5, 24.2R2\u2011S2, 24.4R1\u2011S3, 24.4R2, 25.2R1 or any later version", "If an upgrade cannot be performed immediately, restrict traffic to the UTM Web\u2011Filtering port to only trusted, authenticated sources or isolate the SRX in a separate network segment", "Maintain a rapid incident response plan so that, if a crash occurs, the device can be rebooted and service restored quickly"], "summary": {"action": "Immediate Patch", "impact": "Denial of Service"}, "threat_synthesis": {"affected_systems": "The vulnerability affects Juniper Networks Junos OS running on the SRX Series, including models SRX1500, SRX1600, SRX2300, SRX300, SRX320, SRX340, SRX345, SRX380, SRX4100, SRX4120, SRX4200, SRX4300, SRX4600, SRX4700, SRX5400, SRX5600, and SRX5800. Versions of Junos OS up to 23.2R2\u2011S4, 23.4R2\u2011S4, 24.2R2\u2011S1, 24.4R1\u2011S2, 24.4R2 and earlier are impacted; the flaw is patched in 23.2R2\u2011S5, 23.4R2\u2011S5, 24.2R2\u2011S2, 24.4R1\u2011S3, 24.4R2, 25.2R1 and all subsequent releases.", "description_and_impact": "An improperly validated SSL packet received by the UTM Web-Filtering module of Juniper Networks Junos OS can trigger a crash of the Forwarding Plane Cache (FPC) and force a device restart, thereby disrupting network connectivity for anyone relying on the SRX router. The flaw resides in the syntactic validation of input data; a specifically malformed SSL packet can overwrite or corrupt memory used by the FPC, leading to a denial\u2011of\u2011service condition. Because this crash occurs during normal packet processing, any attacker able to send traffic to the filtered port can potentially cause the outage with no authentication required.", "risk_and_exploitability": "The CVSS score of 8.7 classifies this as high\u2011severity due to its denial\u2011of\u2011service impact and lack of authentication. EPSS is reported as less than 1% so the probability of exploitation in the wild is currently low, though the vector is simple: an unauthenticated attacker can craft a malformed SSL packet and send it over the network. The issue is not listed in the CISA KEV catalog, indicating that no publicly documented exploit exists at this time. Nevertheless, because the flaw can bring the device down without any user interaction, organizations should consider it a significant risk, especially in environments where the SRX handles critical traffic."}}}}, "created": "2026-01-16T13:43:04.949508+00:00", "updated": "2026-04-18T06:00:08.504229+00:00", "vendors": ["juniper", "juniper$PRODUCT$srx", "juniper$PRODUCT$srx_series", "juniper_networks", "juniper_networks$PRODUCT$junos_os"]}