CVE-2025-21599

Junos OS Evolved: Receipt of specifically malformed IPv6 packets causes kernel memory exhaustion leading to Denial of Service

HIGH
7.5
CVSS Score
Published: January 9, 2025 at 04:46 PM UTC
Updated: June 17, 2026 at 08:43 AM UTC
2 products affected across 2 vendorsJunos OS EvolvedJunos OS Evolved

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

Description

A Missing Release of Memory after Effective Lifetime vulnerability in the Juniper Tunnel Driver (jtd) of Juniper Networks Junos OS Evolved allows an unauthenticated network-based attacker to cause Denial of Service. Receipt of specifically malformed IPv6 packets, destined to the device, causes kernel memory to not be freed, resulting in memory exhaustion leading to a system crash and Denial of Service (DoS). Continuous receipt and processing of these packets will continue to exhaust kernel memory, creating a sustained Denial of Service (DoS) condition. This issue only affects systems configured with IPv6. This issue affects Junos OS Evolved: * from 22.4-EVO before 22.4R3-S5-EVO,  * from 23.2-EVO before 23.2R2-S2-EVO,  * from 23.4-EVO before 23.4R2-S2-EVO,  * from 24.2-EVO before 24.2R1-S2-EVO, 24.2R2-EVO. This issue does not affect Juniper Networks Junos OS Evolved versions prior to 22.4R1-EVO.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

22.4-EVO ≤ v < 22.4R3-S5-EVO23.2-EVO ≤ v < 23.2R2-S2-EVO23.4-EVO ≤ v < 23.4R2-S2-EVO24.2-EVO ≤ v < 24.2R1-S2-EVO, 24.2R2-EVO22.4-EVO23.2-EVO23.4-EVO24.2-EVO
Affected range stops below 22.4R3-S5-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 23.2R2-S2-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 23.4R2-S2-EVO, so it looks safe — our inference, not a vendor statement
Affected range stops below 24.2R1-S2-EVO, 24.2R2-EVO, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHjuniper
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-401

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