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OpenAdvisories
Medium · 6.5 CVE-2026-21909 EUVD-2026-2696GHSA-cf3w-5gm7-wvp9

Junos OS and Junos OS Evolved: Receipt of specific IS-IS update packet causes memory leak leading to RPD crash

Published Jan 15, 2026 · Updated Jan 15, 2026 · Assigned by juniper

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.

Affected products

VendorProductAffectedFixed
Juniper Networks Junos OS 23.2 – < 23.2R2, 23.4 – < 23.4R1-S2, 23.4R2, 24.1 – < 24.1R2 23.2R2
Juniper Networks Junos OS Evolved 23.2 – < 23.2R2-EVO, 23.4 – < 23.4R1-S2-EVO, 23.4R2-EVO, 24.1 – < 24.1R2-EVO 23.2R2-EVO

Advisories 2

References