{"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":"2026-07-09T21:01:31.334Z"},"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"}}}}