{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-21909","assignerOrgId":"8cbe9d5a-a066-4c94-8978-4b15efeae968","state":"PUBLISHED","assignerShortName":"juniper","dateReserved":"2026-01-05T17:32:48.710Z","datePublished":"2026-01-15T20:22:44.674Z","dateUpdated":"2026-01-15T20:52:42.400Z"},"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Junos OS","vendor":"Juniper Networks","versions":[{"lessThan":"23.2R2","status":"affected","version":"23.2","versionType":"semver"},{"lessThan":"23.4R1-S2, 23.4R2","status":"affected","version":"23.4","versionType":"semver"},{"lessThan":"24.1R2","status":"affected","version":"24.1","versionType":"semver"},{"lessThan":"23.2R1","status":"unaffected","version":"0","versionType":"semver"}]},{"defaultStatus":"unaffected","product":"Junos OS Evolved","vendor":"Juniper Networks","versions":[{"lessThan":"23.2R2-EVO","status":"affected","version":"23.2","versionType":"semver"},{"lessThan":"23.4R1-S2-EVO, 23.4R2-EVO","status":"affected","version":"23.4","versionType":"semver"},{"lessThan":"24.1R2-EVO","status":"affected","version":"24.1","versionType":"semver"},{"lessThan":"23.2R1-EVO","status":"unaffected","version":"0","versionType":"semver"}]}],"configurations":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"This issue affects systems with IS-IS configured. For example:

[protocols isis interface lo.0 ...]
\n\n[protocols isis interface <interface> ...]
[interfaces <interface> unit <n> family iso]"}],"value":"This issue affects systems with IS-IS configured. For example:\n\n[protocols isis interface lo.0 ...]\n\n\n[protocols isis interface ...]\n[interfaces unit family iso]"}],"datePublic":"2026-01-14T17:00:00.000Z","descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"A Missing Release of Memory after Effective Lifetime vulnerability in the routing protocol daemon (rpd) Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated attacker controlling an adjacent IS-IS neighbor to send a specific update packet causing a memory leak. Continued receipt and processing of these packets will exhaust all available memory, crashing rpd and creating a Denial of Service (DoS) condition.

Memory usage can be monitored through the use of the 'show task memory detail' command. For example:

user@junos> show task memory detail | match ted-infra
  TED-INFRA-COOKIE           25   1072     28   1184     229

\n\nuser@junos> \n\nshow task memory detail | match ted-infra
  TED-INFRA-COOKIE           31   1360     34   1472     307

This issue affects:

Junos OS: 

  • from 23.2 before 23.2R2, 
  • from 23.4 before 23.4R1-S2, 23.4R2, 
  • from 24.1 before 24.1R2; 

Junos OS Evolved: 

  • from 23.2 before 23.2R2-EVO, 
  • from 23.4 before 23.4R1-S2-EVO, 23.4R2-EVO, 
  • from 24.1 before 24.1R2-EVO.
This issue does not affect Junos OS versions before 23.2R1 or Junos OS Evolved versions before 23.2R1-EVO."}],"value":"A Missing Release of Memory after Effective Lifetime vulnerability in the routing protocol daemon (rpd) Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated attacker controlling an adjacent IS-IS neighbor to send a specific update packet causing a memory leak. Continued receipt and processing of these packets will exhaust all available memory, crashing rpd and creating a Denial of Service (DoS) condition.\n\nMemory usage can be monitored through the use of the 'show task memory detail' command. For example:\n\nuser@junos> show task memory detail | match ted-infra\n  TED-INFRA-COOKIE           25   1072     28   1184     229\n\n\n\nuser@junos> \n\nshow task memory detail | match ted-infra\n  TED-INFRA-COOKIE           31   1360     34   1472     307\n\nThis issue affects:\n\nJunos OS: \n\n * from 23.2 before 23.2R2, \n * from 23.4 before 23.4R1-S2, 23.4R2, \n * from 24.1 before 24.1R2; \n\n\nJunos OS Evolved: \n\n * from 23.2 before 23.2R2-EVO, \n * from 23.4 before 23.4R1-S2-EVO, 23.4R2-EVO, \n * from 24.1 before 24.1R2-EVO.\n\n\nThis issue does not affect Junos OS versions before 23.2R1 or Junos OS Evolved versions before 23.2R1-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":"ADJACENT_NETWORK","availabilityImpact":"HIGH","baseScore":6.5,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:A/AC:L/PR:N/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":"ADJACENT","baseScore":7.1,"baseSeverity":"HIGH","privilegesRequired":"NONE","providerUrgency":"GREEN","subAvailabilityImpact":"LOW","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"CONCENTRATED","vectorString":"CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/V:C/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-401","description":"CWE-401 Missing Release of Memory after Effective Lifetime","lang":"en","type":"CWE"}]}],"providerMetadata":{"orgId":"8cbe9d5a-a066-4c94-8978-4b15efeae968","shortName":"juniper","dateUpdated":"2026-01-15T20:22:44.674Z"},"references":[{"tags":["vendor-advisory"],"url":"https://supportportal.juniper.net/JSA106008"},{"tags":["vendor-advisory"],"url":"https://kb.juniper.net/JSA106008"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"The following software releases have been updated to resolve this specific issue:
Junos OS: 23.2R2, 23.4R1-S2, 23.4R2, 24.1R2, 24.2R1, and all subsequent releases.\n\n
Junos OS Evolved: 23.2R2-EVO, 23.4R1-S2-EVO, 23.4R2-EVO, 24.1R2-EVO, 24.2R1-EVO, and all subsequent releases.\n\n


"}],"value":"The following software releases have been updated to resolve this specific issue:\nJunos OS: 23.2R2, 23.4R1-S2, 23.4R2, 24.1R2, 24.2R1, and all subsequent releases.\n\n\n Junos OS Evolved: 23.2R2-EVO, 23.4R1-S2-EVO, 23.4R2-EVO, 24.1R2-EVO, 24.2R1-EVO, and all subsequent releases."}],"source":{"advisory":"JSA106008","defect":["1793982"],"discovery":"USER"},"title":"Junos OS and Junos OS Evolved: Receipt of specific IS-IS update packet causes memory leak leading to RPD 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":"2026-01-15T20:52:37.531214Z","id":"CVE-2026-21909","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":"2026-01-15T20:52:42.400Z"}}]}}