Junos OS (SRX firewalls)
CVE-2025-21595: In an EVPN-VXLAN scenario specific ARP or NDP packets cause FPC to crash
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).
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| Junos OS 0 | 21.2R3-S7 or later |
| Junos OS 21.4 | 21.4R3-S4 or later |
| Junos OS 22.2 | 22.2R3-S1 or later |
| Junos OS 22.3 | 22.3R3-S1 or later |
| Junos OS 22.4 | 22.4R2-S2, 22.4R3 or later |
| Junos OS Evolved 0 | 21.2R3-S7-EVO or later |
| Junos OS Evolved 21.4-EVO | 21.4R3-S4-EVO or later |
| Junos OS Evolved 22.2-EVO | 22.2R3-S1-EVO or later |
| Junos OS Evolved 22.3-EVO | 22.3R3-S1-EVO or later |
| Junos OS Evolved 22.4-EVO | 22.4R3-EVO or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Am I affected?
To be exposed to this issue the device must be configured for EVPN-VXLAN. Refer to product documentation for how to configure EVPN-VXLAN as there are different configuration options.
Workarounds
There are no known workarounds for this issue.
Exploitation
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 13 Oct 2026.