CVE-2025-21595

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.