Vulnerability in Juniper Junos
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.
EPSS: 0.002 (16.0th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
- Juniper Junos — versions 21.2, 21.4, 22.2
- Juniper Junos_os_evolved — versions 21.2, 21.4, 22.2
- Juniper Networks Junos Os — versions 0, 21.4, 22.2
- Juniper Networks Junos Os Evolved — versions 0, 21.4-EVO, 22.2-EVO
Weakness classification (CWE)
References
- sirt@juniper.net (vendor-advisory, Vendor Advisory)
Frequently asked questions
- What is CVE-2025-21595?
- CVE-2025-21595 is a medium-severity vulnerability in Juniper Junos, classified under Missing Release of Memory after Effective Lifetime. CVSS score: 6.5/10. Published 2025-04-09.
- How severe is CVE-2025-21595?
- Medium severity. CVSS v3 base score is 6.5 out of 10.