{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-21921", "assignerOrgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "state": "PUBLISHED", "assignerShortName": "juniper", "dateReserved": "2026-01-05T17:32:48.712Z", "datePublished": "2026-01-15T20:28:29.656Z", "dateUpdated": "2026-01-15T20:55:25.182Z" }, "containers": { "cna": { "affected": [ { "defaultStatus": "unaffected", "product": "Junos OS", "vendor": "Juniper Networks", "versions": [ { "lessThan": "22.4R3-S8", "status": "affected", "version": "0", "versionType": "semver" }, { "lessThan": "23.2R2-S5", "status": "affected", "version": "23.2", "versionType": "semver" }, { "lessThan": "23.4R2", "status": "affected", "version": "23.4", "versionType": "semver" } ] }, { "defaultStatus": "unaffected", "product": "Junos OS Evolved", "vendor": "Juniper Networks", "versions": [ { "lessThan": "22.4R3-S8-EVO", "status": "affected", "version": "0", "versionType": "semver" }, { "lessThan": "23.2R2-S5-EVO", "status": "affected", "version": "23.2", "versionType": "semver" }, { "lessThan": "23.4R2-EVO", "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:

[ system services extension-service request-response grpc ]\n\n
" } ], "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 Use After Free vulnerability in the chassis daemon (chassisd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-based attacker authenticated with low privileges to cause a Denial-of-Service (DoS).

When telemetry collectors are frequently subscribing and unsubscribing to sensors continuously over a long period of time, telemetry-capable processes like chassisd, rpd or mib2d will crash and restart, which - depending on the process - can cause a complete outage until the system has recovered.

This issue affects:

 Junos OS: 

Junos OS Evolved:

" } ], "value": "A Use After Free vulnerability in the chassis daemon (chassisd) of Juniper Networks Junos OS and Junos OS Evolved allows a network-based attacker authenticated with low privileges to cause a Denial-of-Service (DoS).\n\nWhen telemetry collectors are frequently subscribing and unsubscribing to sensors continuously over a long period of time, telemetry-capable processes like chassisd, rpd or mib2d will crash and restart, which - depending on the process - can cause a complete outage until the system has recovered.\n\nThis issue affects:\n\n Junos OS: \n\n\n\n * all versions before 22.4R3-S8,\n * 23.2 versions before 23.2R2-S5,\n * 23.4 versions before 23.4R2;\n\n\n\n\nJunos OS Evolved:\n\n\n\n * all versions before 22.4R3-S8-EVO,\n * 23.2 versions before 23.2R2-S5-EVO,\n * 23.4 versions before 23.4R2-EVO." } ], "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": "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" }, "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ] }, { "cvssV4_0": { "Automatable": "YES", "Recovery": "AUTOMATIC", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "NONE", "attackVector": "NETWORK", "baseScore": 7.1, "baseSeverity": "HIGH", "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/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-416", "description": "CWE-416 Use After Free", "lang": "en", "type": "CWE" } ] } ], "providerMetadata": { "orgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "shortName": "juniper", "dateUpdated": "2026-01-15T20:28:29.656Z" }, "references": [ { "tags": [ "vendor-advisory" ], "url": "https://supportportal.juniper.net/JSA106021" }, { "tags": [ "vendor-advisory" ], "url": "https://kb.juniper.net/JSA106021" } ], "solutions": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "The following software releases have been updated to resolve this specific issue:
Junos OS Evolved: 22.4R3-S8-EVO, 23.2R2-S5-EVO, 23.4R2-EVO, 24.2R1-EVO, and all subsequent releases;
Junos OS: 22.4R3-S8, 23.2R2-S5, 23.4R2, 24.2R1, and all subsequent releases." } ], "value": "The following software releases have been updated to resolve this specific issue:\nJunos OS Evolved: 22.4R3-S8-EVO, 23.2R2-S5-EVO, 23.4R2-EVO, 24.2R1-EVO, and all subsequent releases;\nJunos OS: 22.4R3-S8, 23.2R2-S5, 23.4R2, 24.2R1, and all subsequent releases." } ], "source": { "advisory": "JSA106021", "defect": [ "1791928" ], "discovery": "INTERNAL" }, "title": "Junos OS and Junos OS Evolved: When telemetry collectors are frequently subscribing and unsubscribing to sensors chassisd or rpd will 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": "2026-01-15T20:54:58.001808Z", "id": "CVE-2026-21921", "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": "2026-01-15T20:55:25.182Z" } } ] } }