Vulnerability Database

320,453

Total vulnerabilities in the database

CVE-2026-21909

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.

  • Published: Jan 15, 2026
  • Updated: Jan 16, 2026
  • CVE: CVE-2026-21909
  • Severity: Medium
  • Exploit:

CVSS v3:

  • Severity: Medium
  • Score: 6.5
  • AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWEs: