{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-21901", "assignerOrgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "state": "PUBLISHED", "assignerShortName": "juniper", "dateReserved": "2026-01-05T17:32:48.709Z", "datePublished": "2026-07-09T21:01:31.334Z", "dateUpdated": "2026-07-10T14:21:31.624Z" }, "containers": { "cna": { "affected": [ { "defaultStatus": "unaffected", "product": "Junos OS", "vendor": "Juniper Networks", "versions": [ { "lessThan": "22.3R3-S5", "status": "affected", "version": "22.3", "versionType": "custom" }, { "lessThan": "22.4R3-S10", "status": "affected", "version": "22.4", "versionType": "custom" }, { "lessThan": "23.2R2-S7", "status": "affected", "version": "23.2", "versionType": "custom" }, { "lessThan": "23.4R2-S8", "status": "affected", "version": "23.4", "versionType": "custom" }, { "lessThan": "22.3R1", "status": "unaffected", "version": "0", "versionType": "custom" } ] }, { "defaultStatus": "unaffected", "product": "Junos OS Evolved", "vendor": "Juniper Networks", "versions": [ { "lessThan": "23.2R2-S7-EVO", "status": "affected", "version": "23.2", "versionType": "custom" }, { "lessThan": "23.4R2-S8-EVO", "status": "affected", "version": "23.4", "versionType": "custom" }, { "lessThan": "22.3R1-EVO", "status": "unaffected", "version": "0", "versionType": "custom" } ] } ], "credits": [ { "lang": "en", "type": "finder", "value": "Juniper SIRT would like to acknowledge and thank Orange CERT-CC from the Orange group for responsibly reporting this vulnerability." } ], "datePublic": "2026-07-08T16:00:00.000Z", "descriptions": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "A NULL Pointer Dereference vulnerability in the management daemon (mgd) of Juniper Networks Junos OS and Junos OS Evolved allows a local, high-privileged attacker setting or deactivating a specific SSH configuration parameter to create a Denial of Service (DoS).

A local high-privileged user configuring or deactivating a specific 'system services ssh' configuration parameter can exploit a null pointer dereference in one of the functions used by SSH. The function attempts to dereference a null pointer when accessing certain configuration data, resulting in an mgd process crash and restart. Continued execution of these configuration commands will create a sustained Denial of Service (DoS) condition.


This issue affects:
Junos OS:

\n\nThis issue does not affect Junos OS before 22.3R1.\n\n

Junos OS Evolved:
This issue does not affect Junos OS Evolved before 22.3R1-EVO.

" } ], "value": "A NULL Pointer Dereference vulnerability in the management daemon (mgd) of Juniper Networks Junos OS and Junos OS Evolved allows a local, high-privileged attacker setting or deactivating a specific SSH configuration parameter to create a Denial of Service (DoS).\n\nA local high-privileged user configuring or deactivating a specific 'system services ssh' configuration parameter can exploit a null pointer dereference in one of the functions used by SSH. The function attempts to dereference a null pointer when accessing certain configuration data, resulting in an mgd process crash and restart. Continued execution of these configuration commands will create a sustained Denial of Service (DoS) condition.\n\nThis issue affects:\nJunos OS:\n\n\n * from 22.3 before 22.3R3-S5;\n * from 22.4 before 22.4R3-S10;\n * from 23.2 before 23.2R2-S7;\n * from 23.4 before 23.4R2-S8.\n\n\n\n\nThis issue does not affect Junos OS before 22.3R1.\n\n\n\nJunos OS Evolved:\n * from 22.3R1-EVO before 23.2R2-S7-EVO;\n * from 23.4 before 23.4R2-S8-EVO.\n\n\nThis issue does not affect Junos OS Evolved before 22.3R1-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": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 4.4, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "HIGH", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:H/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": "LOCAL", "baseScore": 6.7, "baseSeverity": "MEDIUM", "privilegesRequired": "HIGH", "providerUrgency": "GREEN", "subAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "DIFFUSE", "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/AU:Y/R:A/V:D/RE:M/U:Green", "version": "4.0", "vulnAvailabilityImpact": "HIGH", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "MODERATE" }, "format": "CVSS", "scenarios": [ { "lang": "en", "value": "GENERAL" } ] } ], "problemTypes": [ { "descriptions": [ { "cweId": "CWE-476", "description": "CWE-476 NULL Pointer Dereference", "lang": "en", "type": "CWE" } ] } ], "providerMetadata": { "orgId": "8cbe9d5a-a066-4c94-8978-4b15efeae968", "shortName": "juniper", "dateUpdated": "2026-07-09T21:01:31.334Z" }, "references": [ { "tags": [ "third-party-advisory" ], "url": "https://github.com/orangecertcc/security-research/security/advisories/GHSA-g4f7-w2rc-hpj6" }, { "tags": [ "vendor-advisory" ], "url": "https://supportportal.juniper.net/JSA110072" } ], "solutions": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "The following software releases have been updated to resolve this specific issue:
Junos OS: 22.3R3-S5, 22.4R3-S10, 23.2R2-S7, 23.4R2-S8, 24.2R1, and all subsequent releases.\n
\nJunos OS Evolved: 23.2R2-S7-EVO, 23.4R2-S8-EVO, 24.2R1-EVO, and all subsequent releases." } ], "value": "The following software releases have been updated to resolve this specific issue:\nJunos OS: 22.3R3-S5, 22.4R3-S10, 23.2R2-S7, 23.4R2-S8, 24.2R1, and all subsequent releases.\n\n\nJunos OS Evolved: 23.2R2-S7-EVO, 23.4R2-S8-EVO, 24.2R1-EVO, and all subsequent releases." } ], "source": { "advisory": "JSA110072", "defect": [ "1779319" ], "discovery": "EXTERNAL" }, "title": "Junos OS and Junos OS Evolved: Configuration of a specific SSH option results in mgd crash", "workarounds": [ { "lang": "en", "supportingMedia": [ { "base64": false, "type": "text/html", "value": "There are no direct workarounds for this issue.

\n\nOne of the following mitigations will prevent malicious exploitation:
" } ], "value": "There are no direct workarounds for this issue.\n\n\n\nOne of the following mitigations will prevent malicious exploitation:\n\n\n\n\n * Use access lists or firewall filters to limit access to the CLI only from trusted hosts and administrators.\n * Utilize command authorization to limit the ability to enter config mode to trusted administrators." } ], "x_generator": { "engine": "Vulnogram 0.1.0-dev" } }, "adp": [ { "references": [ { "url": "https://github.com/orangecertcc/security-research/security/advisories/GHSA-g4f7-w2rc-hpj6", "tags": [ "exploit" ] } ], "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-07-10T14:21:27.704515Z", "id": "CVE-2026-21901", "options": [ { "Exploitation": "poc" }, { "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": "2026-07-10T14:21:31.624Z" } } ] } }