Junos Os Evolved
CVE-2026-21909
MEDIUM
Severity by source
AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
2DescriptionCVE.org
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
user@junos>
show 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.
AnalysisAI
Denial of service in Juniper Junos OS and Junos OS Evolved allows an adjacent IS-IS neighbor to trigger a memory leak in the routing protocol daemon by sending specially crafted update packets. Repeated exploitation exhausts available memory and crashes the rpd process, rendering routing unavailable. No patch is currently available.
Technical ContextAI
Classified as CWE-401 (Memory Leak). Affects Junos. 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
RemediationAI
Monitor vendor advisories for a patch.
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Same weakness CWE-401 – Memory Leak
View allSame technique Denial Of Service
View allShare
External POC / Exploit Code
Leaving vuln.today