Summary
A Missing Release of Memory after Effective Lifetime vulnerability in the Packet Forwarding...
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.
Impact
CVE-2025-21595 has a CVSS score of 6.5 (High). The vector is reachable from an adjacent network, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2025-21595? CVE-2025-21595 is a high-severity security vulnerability. No fixed version is listed yet.
- How severe is CVE-2025-21595? CVE-2025-21595 has a CVSS score of 6.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Is there a fix for CVE-2025-21595? No fixed version is listed for CVE-2025-21595 yet. Monitor the advisory for updates and apply mitigations in the interim.
- Is CVE-2025-21595 exploitable, and should I be worried? Whether CVE-2025-21595 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2025-21595 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.