CVE-2025-21599 – Juniper Networks Junos OS Evolved IPv6 Malformed Packet Memory Exhaustion Denial of Service

CVE ID : CVE-2025-21599

Published : Jan. 9, 2025, 5:15 p.m. | 1 hour ago

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.

Severity: 7.5 | HIGH

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CVE-2025-21599 – Juniper Networks Junos OS Evolved IPv6 Malformed Packet Memory Exhaustion Denial of Service