CVE-2025-21595: Junos OS and Junos OS Evolved: In an EVPN-VXLAN scenario specific ARP or NDP packets cause FPC to crash
First published: Wed Apr 09 2025(Updated: )
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.
Credit: sirt@juniper.net
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Juniper JUNOS | <21.2R3-S7<21.4R3-S4<22.2R3-S1<22.3R3-S1<22.4R2-S2<22.4R3 | |
| Juniper Networks Junos OS | <21.2R3-S7-EVO<21.4R3-S4-EVO<22.2R3-S1-EVO<22.3R3-S1-EVO<22.4R3-EVO |
Remedy
The following software releases have been updated to resolve this specific issue. Junos OS: 21.2R3-S7, 21.4R3-S4, 22.2R3-S1, 22.3R3-S1, 22.4R2-S2, 22.4R3, 23.2R1, and all subsequent releases. Junos OS Evolved: 21.2R3-S7-EVO, 21.4R3-S4-EVO, 22.2R3-S1-EVO, 22.3R3-S1-EVO, 22.4R3-EVO, 23.2R1-EVO, and all subsequent releases.
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Reference Links
Frequently Asked Questions
What is the severity of CVE-2025-21595?
CVE-2025-21595 is classified as a critical vulnerability due to its potential to cause Denial of Service (DoS) by allowing an unauthenticated attacker to crash the affected system.
How do I fix CVE-2025-21595?
To remediate CVE-2025-21595, you should upgrade your Junos OS or Junos OS Evolved to the versions that are not affected by this vulnerability as specified by Juniper Networks.
Which versions of Junos OS are affected by CVE-2025-21595?
CVE-2025-21595 affects Junos OS versions up to 21.2R3-S7, 21.4R3-S4, 22.2R3-S1, 22.3R3-S1, 22.4R2-S2, and 22.4R3.
Who can exploit CVE-2025-21595?
CVE-2025-21595 can be exploited by an adjacent, unauthenticated attacker.
What impact does CVE-2025-21595 have on my network?
Exploitation of CVE-2025-21595 can lead to a Denial of Service (DoS), disrupting network operations by crashing the affected forwarding components.
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