Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-21909

Severity CVSS v4.0:
HIGH
Type:
Unavailable / Other
Publication date:
15/01/2026
Last modified:
23/01/2026

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.<br /> <br /> Memory usage can be monitored through the use of the &amp;#39;show task memory detail&amp;#39; command. For example:<br /> <br /> user@junos&gt; show task memory detail | match ted-infra<br />   TED-INFRA-COOKIE           25   1072     28   1184     229<br /> <br /> <br /> <br /> user@junos&gt; <br /> <br /> show task memory detail | match ted-infra<br />   TED-INFRA-COOKIE           31   1360     34   1472     307<br /> <br /> This issue affects:<br /> <br /> Junos OS: <br /> <br /> * from 23.2 before 23.2R2, <br /> * from 23.4 before 23.4R1-S2, 23.4R2, <br /> * from 24.1 before 24.1R2; <br /> <br /> <br /> Junos OS Evolved: <br /> <br /> * from 23.2 before 23.2R2-EVO, <br /> * from 23.4 before 23.4R1-S2-EVO, 23.4R2-EVO, <br /> * from 24.1 before 24.1R2-EVO.<br /> <br /> <br /> This issue does not affect Junos OS versions before 23.2R1 or Junos OS Evolved versions before 23.2R1-EVO.

Impact

Vector 4.0
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 CVSS v4.0 Severity and Metrics:

Base Score: 7.10 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

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): None
Integrity (VI): None
Availability (VA): High
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): Low
Automatable (AU): Yes
Recovery (R): Automatic
Value Density (V): Concentrated
Vulnerability Response Effort (RE): Moderate
Provider Urgency (U): Green

Base Score 4.0
7.10
Severity 4.0
HIGH
Vector 3.x
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H CVSS v3.1 Severity and Metrics:

Base Score: 6.50 MEDIUM
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector (AV): Adjacent
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): High

Base Score 3.x
6.50
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:o:juniper:junos:23.2:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:23.4:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:23.4:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:23.4:r1-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:23.4:r2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:24.1:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:24.1:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:23.2:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:23.2:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:23.4:-:*:*:*:*:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools