# CVE-2025-21599

## Summary

- **CVE ID:** CVE-2025-21599
- **Severity:** HIGH
- **CVSS Score:** 8.7 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L)
- **CWE:** CWE-401
- **Published:** Jan 9, 2025
- **Last Modified:** Mar 12, 2026

## 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 Products

- Juniper Networks — Junos OS Evolved (22.4-EVO)
- Juniper Networks — Junos OS Evolved (23.2-EVO)
- Juniper Networks — Junos OS Evolved (23.4-EVO)
- Juniper Networks — Junos OS Evolved (24.2-EVO)

## References

- [CNA](https://supportportal.juniper.net/JSA92869)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.61%
- **EPSS Percentile:** 47.0

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._