CVE-2026-21909

published 2026-01-15

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…

Priority P4 30 medium 6.5 CVSS 3.1

AV A AC L PR N UI N S U C N I N A H

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

13 ranges

Vendor	Product	Version range	Fixed in
juniper	junos	—	—
juniper	junos	—	—
juniper	junos	—	—
juniper	junos_os	—	—
juniper	junos_os_evolved	—	—
juniper	junos_os_evolved	—	—
juniper	junos_os_evolved	—	—
juniper_networks	junos_os	>= 23.2 < 23.2R2	23.2R2
juniper_networks	junos_os	>= 23.4 < 23.4R1-S2, 23.4R2	23.4R1-S2, 23.4R2
juniper_networks	junos_os	>= 24.1 < 24.1R2	24.1R2
juniper_networks	junos_os_evolved	>= 23.2 < 23.2R2-EVO	23.2R2-EVO
juniper_networks	junos_os_evolved	>= 23.4 < 23.4R1-S2-EVO, 23.4R2-EVO	23.4R1-S2-EVO, 23.4R2-EVO
juniper_networks	junos_os_evolved	>= 24.1 < 24.1R2-EVO	24.1R2-EVO

CVSS provenance

nvd v3.1 6.5 MEDIUM CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd v4.0 7.1 HIGH 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:C/RE:M/U:Green

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CWE-401