{"api_version":"1","generated_at":"2026-07-13T15:19:21+00:00","cve":"CVE-2026-21901","urls":{"html":"https://cve.report/CVE-2026-21901","api":"https://cve.report/api/cve/CVE-2026-21901.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-21901","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-21901"},"summary":{"title":"Junos OS and Junos OS Evolved: Configuration of a specific SSH option results in mgd crash","description":"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.","state":"PUBLISHED","assigner":"juniper","published_at":"2026-07-09 21:16:54","updated_at":"2026-07-10 17:49:57"},"problem_types":["CWE-476","CWE-476 CWE-476 NULL Pointer Dereference"],"metrics":[{"version":"4.0","source":"sirt@juniper.net","type":"Secondary","score":"6.7","severity":"MEDIUM","vector":"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/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:D/RE:M/U:Green","data":{"version":"4.0","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/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:D/RE:M/U:Green","baseScore":6.7,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"HIGH","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"YES","Recovery":"AUTOMATIC","valueDensity":"DIFFUSE","vulnerabilityResponseEffort":"MODERATE","providerUrgency":"GREEN"}},{"version":"4.0","source":"CNA","type":"CVSS","score":"6.7","severity":"MEDIUM","vector":"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","data":{"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"}},{"version":"3.1","source":"sirt@juniper.net","type":"Secondary","score":"4.4","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","baseScore":4.4,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"4.4","severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","data":{"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"}}],"references":[{"url":"https://github.com/orangecertcc/security-research/security/advisories/GHSA-g4f7-w2rc-hpj6","name":"https://github.com/orangecertcc/security-research/security/advisories/GHSA-g4f7-w2rc-hpj6","refsource":"134c704f-9b21-4f2e-91b3-4a467353bcc0","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://supportportal.juniper.net/JSA110072","name":"https://supportportal.juniper.net/JSA110072","refsource":"sirt@juniper.net","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-21901","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-21901","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Juniper Networks","product":"Junos OS","version":"affected 22.3 22.3R3-S5 custom","platforms":[]},{"source":"CNA","vendor":"Juniper Networks","product":"Junos OS","version":"affected 22.4 22.4R3-S10 custom","platforms":[]},{"source":"CNA","vendor":"Juniper Networks","product":"Junos OS","version":"affected 23.2 23.2R2-S7 custom","platforms":[]},{"source":"CNA","vendor":"Juniper Networks","product":"Junos OS","version":"affected 23.4 23.4R2-S8 custom","platforms":[]},{"source":"CNA","vendor":"Juniper Networks","product":"Junos OS","version":"unaffected 22.3R1 custom","platforms":[]},{"source":"CNA","vendor":"Juniper Networks","product":"Junos OS Evolved","version":"affected 23.2 23.2R2-S7-EVO custom","platforms":[]},{"source":"CNA","vendor":"Juniper Networks","product":"Junos OS Evolved","version":"affected 23.4 23.4R2-S8-EVO custom","platforms":[]},{"source":"CNA","vendor":"Juniper Networks","product":"Junos OS Evolved","version":"unaffected 22.3R1-EVO custom","platforms":[]}],"timeline":[],"solutions":[{"source":"CNA","title":"","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.","time":"","lang":"en"}],"workarounds":[{"source":"CNA","title":"","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.","time":"","lang":"en"}],"exploits":[{"source":"CNA","title":"","value":"Juniper SIRT is not aware of any malicious exploitation of this vulnerability.","time":"","lang":"en"}],"credits":[{"source":"CNA","value":"Juniper SIRT would like to acknowledge and thank Orange CERT-CC from the Orange group for responsibly reporting this vulnerability.","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"21901","cve":"CVE-2026-21901","epss":"0.001660000","percentile":"0.061060000","score_date":"2026-07-12","updated_at":"2026-07-13 00:07:37"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-21901","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA 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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:
from 22.3 before 22.3R3-S5;
from 22.4 before 22.4R3-S10;
from 23.2 before 23.2R2-S7;
from 23.4 before 23.4R2-S8.
\n\nThis issue does not affect Junos OS before 22.3R1.\n\n
Junos OS Evolved:
from 22.3R1-EVO before 23.2R2-S7-EVO;
from 23.4 before 23.4R2-S8-EVO.
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":{"dateUpdated":"2026-07-09T21:01:31.334Z","orgId":"8cbe9d5a-a066-4c94-8978-4b15efeae968","shortName":"juniper"},"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:
Use access lists or firewall filters to limit access to the CLI only from trusted hosts and administrators.
Utilize command authorization to limit the ability to enter config mode to trusted administrators.
"}],"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"}}},"cveMetadata":{"assignerOrgId":"8cbe9d5a-a066-4c94-8978-4b15efeae968","assignerShortName":"juniper","cveId":"CVE-2026-21901","datePublished":"2026-07-09T21:01:31.334Z","dateReserved":"2026-01-05T17:32:48.709Z","dateUpdated":"2026-07-10T14:21:31.624Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-09 21:16:54","lastModifiedDate":"2026-07-10 17:49:57","problem_types":["CWE-476","CWE-476 CWE-476 NULL Pointer Dereference"],"metrics":{"cvssMetricV40":[{"source":"sirt@juniper.net","type":"Secondary","cvssData":{"version":"4.0","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/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:D/RE:M/U:Green","baseScore":6.7,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"HIGH","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"YES","Recovery":"AUTOMATIC","valueDensity":"DIFFUSE","vulnerabilityResponseEffort":"MODERATE","providerUrgency":"GREEN"}}],"cvssMetricV31":[{"source":"sirt@juniper.net","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H","baseScore":4.4,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"HIGH","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":0.8,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-07-10T14:21:27.704515Z","id":"CVE-2026-21901","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"21901","Ordinal":"1","Title":"Junos OS and Junos OS Evolved: Configuration of a specific SSH o","CVE":"CVE-2026-21901","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"21901","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"Junos OS and Junos OS Evolved: Configuration of a specific SSH o"}]}}}