CVE-2025-21595 Junos OS and Junos OS Evolved: In an EVPN-VXLAN scenario specific ARP or NDP packets cause FPC to crash
Adjacent attackers can crash network line cards by sending specific ARP or NDP packets in EVPN-VXLAN environments, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-21595?
CVE-2025-21595 is a high-severity denial of service vulnerability in Juniper Junos, published on 9 Apr 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A Missing Release of Memory after Effective Lifetime vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker to cause an FPC to crash, leading to Denial of Service (DoS).
On all Junos OS and Junos OS Evolved platforms, in an EVPN-VXLAN scenario, when specific ARP packets are received on an IPv4 network, or specific NDP packets are received on an IPv6 network, kernel heap memory leaks, which eventually leads to an FPC crash and restart.
This issue does not affect MX Series platforms. Heap size growth on FPC can be seen using below command.
user@host> show chassis fpc Temp CPU Utilization (%) CPU Utilization (%) Memory Utilization (%) Slot State (C) Total Interrupt 1min 5min 15min DRAM (MB) Heap Buffer 0 Online 45 3 0 2 2 2 32768 19 0 <<<<<<< Heap increase in all fPCs
This issue affects Junos OS:
* All versions before 21.2R3-S7, * 21.4 versions before 21.4R3-S4, * 22.2 versions before 22.2R3-S1, * 22.3 versions before 22.3R3-S1, * 22.4 versions before 22.4R2-S2, 22.4R3.
and Junos OS Evolved:
* All versions before 21.2R3-S7-EVO, * 21.4-EVO versions before 21.4R3-S4-EVO, * 22.2-EVO versions before 22.2R3-S1-EVO, * 22.3-EVO versions before 22.3R3-S1-EVO,
* 22.4-EVO versions before 22.4R3-EVO.
Weakness: CWE-401
Which versions are affected by CVE-2025-21595?
It affects 2 products.
Products include Juniper Junos, Juniper Junos Os Evolved.
How do I fix CVE-2025-21595?
No fix has been published for CVE-2025-21595 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2025-21595 being exploited?
There is no known exploitation of CVE-2025-21595 in the wild and no public exploit code.
Other vulnerabilities in Juniper Junos
- CVE-2023-36845 Juniper Junos OS EX Series and SRX Series PHP External Variable Modification
- CVE-2020-1631 Juniper Junos OS Path Traversal
- CVE-2025-21590 Juniper Junos OS Improper Isolation or Compartmentalization
- CVE-2023-36851 Juniper Junos OS SRX Series Missing Authentication for Critical Function
- CVE-2023-36844 Juniper Junos OS EX Series PHP External Variable Modification
Sources
Also known as GHSA-7fvw-hrgg-4cr6.