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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
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.
- Record
CVE-2025-21599- CVSS 4.0
- 8.7 High
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 - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-401
- Updated
- 2026-11-02
EUVDEUVD-2025-2565
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.
- Record
EUVD-2025-2565- CVSS 4.0
- 8.7 High
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 - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-p34f-rw7f-c723
A Missing Release of Memory after Effective Lifetime vulnerability in the Juniper Tunnel Driver ...
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.
- Record
GHSA-p34f-rw7f-c723- CVSS 4.0
- 8.7 High
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-401
- Updated
- 2026-11-02
NVD
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.
- Record
CVE-2025-21599- CVSS 4.0
- 8.7 High
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-401
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, published | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-21599 is a high vulnerability (CVSS 8.7) in Juniper Junos Os Evolved, published January 9, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.60%, the 49th percentile. No source names a fixed version.