CVE-2025-21599: Junos OS Evolved: Receipt of specifically malformed IPv6 packets causes kernel memory exhaustion leading to Denial of Service
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 Software
Remediation
Information
Event History
Frequently Asked Questions
What is the severity of CVE-2025-21599?
CVE-2025-21599 is classified as a high severity vulnerability due to its potential to cause Denial of Service.
How do I fix CVE-2025-21599?
To fix CVE-2025-21599, upgrade to the latest version of Junos OS Evolved that addresses this vulnerability.
Who is affected by CVE-2025-21599?
CVE-2025-21599 affects users of Juniper Networks Junos OS Evolved versions 22.4R1-EVO through 24.2-EVO.
What type of attack does CVE-2025-21599 enable?
CVE-2025-21599 allows unauthenticated network-based attackers to conduct Denial of Service attacks.
What specific packet type triggers CVE-2025-21599?
CVE-2025-21599 is triggered by the receipt of specifically malformed IPv6 packets.