Juniper Junos OS up to 25.2R1 Packet Forwarding Engine error condition

Summaryinfo

A vulnerability was found in Juniper Junos OS up to 23.2R2-S6/23.4R2-S6/24.2R2-S2/24.4R2-S1/25.2R1. It has been declared as very critical. This issue affects some unknown processing of the component Packet Forwarding Engine. Such manipulation leads to error condition. This vulnerability is listed as CVE-2026-57031. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in Juniper Junos OS up to 23.2R2-S6/23.4R2-S6/24.2R2-S2/24.4R2-S1/25.2R1 and classified as very critical. Affected by this issue is some unknown processing of the component Packet Forwarding Engine. The manipulation with an unknown input leads to a error condition vulnerability. Using CWE to declare the problem leads to CWE-390. The product detects a specific error, but takes no actions to handle the error. Impacted is confidentiality, integrity, and availability. CVE summarizes:

An Improper Check for Unusual or Exceptional Conditions vulnerability in the packet forwarding engine (PFE) of Juniper Networks Junos OS on MX Series allows adjacent subscribers to bypass configured firewall filters. On MX Series devices with MPC10/11, LC4800/9600, and MX304 with subscribers configured on static interfaces, ingress firewall filters are not enforced, so that neither protocol level nor upstream bandwidth limitation are in effect.  This issue affects Junos OS on MX with MPC10/11, LC4800/9600/4802, and MX304: * 23.2 versions from 23.2R2-S1 before 23.2R2-S7, * 23.4 versions from 23.4R2 before 23.4R2-S7, * 24.2 versions before 24.2R2-S3, * 24.4 versions before 24.4R2-S2, * 25.2 versions before 25.2R2.

The advisory is shared for download at supportportal.juniper.net. This vulnerability is handled as CVE-2026-57031 since 06/23/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 07/10/2026).

Upgrading to version 23.2R2-S7, 23.4R2-S7, 24.2R2-S3, 24.4R2-S2 or 25.2R2 eliminates this vulnerability.

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Productinfo

Type

• Router Operating System

Vendor

• Juniper

Name

• Junos OS

Version

• 23.2R2-S6
• 23.4R2-S6
• 24.2R2-S2
• 24.4R2-S1
• 25.2R1

License

• commercial

Website

• Vendor: https://www.juniper.net/

CPE 2.3info

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