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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-21909 Detail

Description

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

Nist CVSS score does not match with CNA score
CNA:  Juniper Networks, Inc.
CVSS-B 7.1 HIGH
Vector:  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

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://kb.juniper.net/JSA106008 Juniper Networks, Inc. Vendor Advisory 
https://supportportal.juniper.net/JSA106008 Juniper Networks, Inc. Vendor Advisory 

Weakness Enumeration

CWE-ID CWE Name Source
CWE-401 Missing Release of Memory after Effective Lifetime Juniper Networks, Inc.  

Known Affected Software Configurations Switch to CPE 2.2

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Change History

4 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-21909
NVD Published Date:
01/15/2026
NVD Last Modified:
06/17/2026
Source:
Juniper Networks, Inc.