Juniper Networks Junos OS up to 25.2R1-S0 Packet Forwarding Engine use after free

Summaryinfo

A vulnerability, which was classified as critical, has been found in Juniper Networks Junos OS up to 25.2R1-S0. The affected element is an unknown function of the component Packet Forwarding Engine. This manipulation causes use after free. This vulnerability is registered as CVE-2026-102078. Remote exploitation of the attack is possible. No exploit is available. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Juniper Networks Junos OS up to 25.2R1-S0. Affected by this vulnerability is an unknown functionality of the component Packet Forwarding Engine. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect availability. The summary by CVE is:

A Use After Free vulnerability in the packet forwarding engine (pfe) of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS). When web filtering for TCP traffic is configured, a high volume of DNS requests increases the likelihood of a flowd crash and restart, which leads to a complete service outage until the service has automatically recovered. This is a race condition outside the attacker's direct control. This issue affects Junos OS on SRX Series: * All versions before 23.2R2-S5; * from 23.4 before 23.4R2-S6; * from 24.2 before 24.2R2-S3; * from 24.4 before 24.4R2-S1; * from 25.2 before 25.2R1-S1, 25.2R2.

The advisory is shared at supportportal.juniper.net. This vulnerability is known as CVE-2026-102078 since 09/28/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 10/14/2026).

Upgrading to version 23.2R2-S5, 23.4R2-S6, 24.2R2-S3, 24.4R2-S1, 25.2R1-S1 or 25.2R2 eliminates this vulnerability.

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Productinfo

Type

• Router Operating System

Vendor

• Juniper Networks

Name

• Junos OS

Version

• 23.2R2-S4
• 23.4R2-S5
• 24.2R2-S2
• 24.4R2-S0
• 25.2R1
• 25.2R1-S0

License

• commercial

CPE 2.3info

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CPE 2.2info

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