Juniper Junos OS/Junos OS Evolved Packet Forwarding Engine memory leak

Summaryinfo

A vulnerability described as problematic has been identified in Juniper Junos OS and Junos OS Evolved. Affected by this vulnerability is an unknown functionality of the component Packet Forwarding Engine. The manipulation results in memory leak. This vulnerability is known as CVE-2025-21595. Access to the local network is required for this attack. No exploit is available. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in Juniper Junos OS and Junos OS Evolved (unknown version). It has been classified as critical. Affected is an unknown code block of the component Packet Forwarding Engine. The manipulation with an unknown input leads to a memory leak vulnerability. CWE is classifying the issue as CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. This is going to have an impact on availability. CVE summarizes:

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.

The advisory is shared for download at supportportal.juniper.net. This vulnerability is traded as CVE-2025-21595 since 12/26/2024. The exploitability is told to be easy. Access to the local network is required for this attack. The exploitation doesn't require any form of authentication. There are neither technical details nor an exploit publicly available.

Upgrading eliminates this vulnerability.

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Productinfo

Type

• Router Operating System

Vendor

• Juniper

Name

• Junos OS
• Junos OS Evolved

License

• commercial

Website

• Vendor: https://www.juniper.net/

CPE 2.3info

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CPE 2.2info

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Entryinfo

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