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Fencer Vulns
medium 6.5

CVE-2025-21595 json

Junos OS and Junos OS Evolved: In an EVPN-VXLAN scenario specific ARP or NDP packets cause FPC to crash

published 2025-04-09 19 mo ago modified 2026-06-17 4 mo ago also EUVD-2025-10527

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 18%
public exploits
0
none known

Summary

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.

Patch / fix

  • Juniper Networks Junos OS 21.2R3-S7, 21.4R3-S4, 22.2R3-S1, 22.3R3-S1, 22.4R2-S2, 22.4R3
  • Juniper Networks Junos OS Evolved 21.2R3-S7-EVO, 21.4R3-S4-EVO, 22.2R3-S1-EVO, 22.3R3-S1-EVO, 22.4R3-EVO

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
18 mo ago

Exploit prediction

0.26% chance of exploitation in the next 30 days, higher than 18% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 7.1 CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L
CNA 4.0 7.1 CVSS:4.0/AV:A/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

Affected products

  • Juniper Networks Junos OS
  • Juniper Networks Junos OS Evolved

Classification

Weakness
  • CWE-401 Missing Release of Memory after Effective Lifetime

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.