{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-21903", "assignerOrgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "state": "PUBLISHED", "assignerShortName": "juniper", "dateReserved": "2026-01-05T17:32:48.709Z", "datePublished": "2026-01-15T20:18:36.767Z", "dateUpdated": "2026-01-15T21:12:08.631Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Junos OS", "vendor": "Juniper Networks", "versions": [{"lessThan": "22.4R3-S7", "status": "affected", "version": "0", "versionType": "semver"}, {"lessThan": "23.2R2-S4", "status": "affected", "version": "23.2", "versionType": "semver"}, {"lessThan": "23.4R2", "status": "affected", "version": "23.4", "versionType": "semver"}]}], "configurations": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "A device is only exposed to this issue if GRPC services are configured:<br><br><tt>[ system services extension-service request-response grpc ]</tt>"}], "value": "A device is only exposed to this issue if GRPC services are configured:\n\n[ system services extension-service request-response grpc ]"}], "datePublic": "2026-01-14T17:00:00.000Z", "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker,&nbsp;<span style=\"background-color: rgb(255, 255, 255);\">authenticated</span>&nbsp;with low privileges to cause a Denial-of-Service (DoS).<br><br>\n\n<span style=\"background-color: rgb(255, 255, 255);\">Subscribing to telemetry sensors at scale causes all FPC connections to drop, resulting in an FPC crash and restart.<br>The issue was not seen when YANG packages for the specific sensors were installed. </span>\n\n<br><br><p>This issue affects Junos OS:&nbsp;</p><p></p><ul><li>all versions before 22.4R3-S7,</li><li>23.2 version before 23.2R2-S4,</li><li>23.4 versions before 23.4R2.</li></ul><p></p><p><br></p>"}], "value": "A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker,\u00a0authenticated\u00a0with low privileges to cause a Denial-of-Service (DoS).\n\n\n\nSubscribing to telemetry sensors at scale causes all FPC connections to drop, resulting in an FPC crash and restart.\nThe issue was not seen when YANG packages for the specific sensors were installed. \n\n\n\nThis issue affects Junos OS:\u00a0\n\n\n\n * all versions before 22.4R3-S7,\n * 23.2 version before 23.2R2-S4,\n * 23.4 versions before 23.4R2."}], "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."}], "metrics": [{"cvssV3_1": {"attackComplexity": 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23.2R2-S4, 23.4R2, 24.2R1, and all subsequent releases."}], "source": {"advisory": "JSA106022", "defect": ["1811989"], "discovery": "INTERNAL"}, "title": "Junos OS: Subscribing to telemetry sensors at scale causes all FPCs to crash", "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": [{"metrics": [{"other": {"type": "ssvc", "content": {"timestamp": "2026-01-15T21:12:00.833031Z", "id": "CVE-2026-21903", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "partial"}], "role": "CISA Coordinator", "version": "2.0.3"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-01-15T21:12:08.631Z"}}]}}

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{"cveTags": [], "descriptions": [{"lang": "en", "value": "A Stack-based Buffer Overflow vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS allows a network-based attacker,\u00a0authenticated\u00a0with low privileges to cause a Denial-of-Service (DoS).\n\n\n\nSubscribing to telemetry sensors at scale causes all FPC connections to drop, resulting in an FPC crash and restart.\nThe issue was not seen when YANG packages for the specific sensors were installed. \n\n\n\nThis issue affects Junos OS:\u00a0\n\n\n\n * all versions before 22.4R3-S7,\n * 23.2 version before 23.2R2-S4,\n * 23.4 versions before 23.4R2."}], "id": "CVE-2026-21903", "lastModified": "2026-01-15T21:16:05.807", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "[email protected]", "type": "Primary"}], "cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 7.1, "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": "LOW", "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:L/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:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "[email protected]", "type": "Secondary"}]}, "published": "2026-01-15T21:16:05.807", "references": [{"source": "[email protected]", "url": "https://kb.juniper.net/JSA106022"}, {"source": "[email protected]", "url": "https://supportportal.juniper.net/JSA106022"}], "sourceIdentifier": "[email protected]", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-121"}], "source": "[email protected]", "type": "Primary"}]}

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