Vulnerability record · CVE-2025-59957 · published 9 October 2025
CVE-2025-59957: Juniper junos origin validation error vulnerability
Juniper · Junos
An Origin Validation Error vulnerability in an insufficient protected file of Juniper Networks Junos OS on EX4600 Series and QFX5000 Series allows an unauthenticated attacker with physical access to the device to create a backdoor which allows complete control of the system. When a device isn't configured with a root password, an attacker can modify a specific file. It's contents will be added to the Junos configuration of the device without being visible. This allows for the addition of any configuration unknown to the actual operator, which includes users, IP addresses and other configuration which could allow unauthorized access to the device. This exploit is persistent across reboots and even zeroization. The indicator of compromise is a modified /etc/config/<platform>-defaults[-flex].conf file. Review that file for unexpected configuration statements, or compare it to an unmodified version which can be extracted from the original Juniper software image file. For details on the extraction procedure please contact Juniper Technical Assistance Center (JTAC). To restore the device to a trusted initial configuration the system needs to be reinstalled from physical media. This issue affects Junos OS on EX4600 Series and QFX5000 Series: * All versions before 21.4R3, * 22.2 versions before 22.2R3-S3.
Description
An Origin Validation Error vulnerability in an insufficient protected file of Juniper Networks Junos OS on EX4600 Series and QFX5000 Series allows an unauthenticated attacker with physical access to the device to create a backdoor which allows complete control of the system. When a device isn't configured with a root password, an attacker can modify a specific file. It's contents will be added to the Junos configuration of the device without being visible. This allows for the addition of any configuration unknown to the actual operator, which includes users, IP addresses and other configuration which could allow unauthorized access to the device. This exploit is persistent across reboots and even zeroization. The indicator of compromise is a modified /etc/config/<platform>-defaults[-flex].conf file. Review that file for unexpected configuration statements, or compare it to an unmodified version which can be extracted from the original Juniper software image file. For details on the extraction procedure please contact Juniper Technical Assistance Center (JTAC). To restore the device to a trusted initial configuration the system needs to be reinstalled from physical media. This issue affects Junos OS on EX4600 Series and QFX5000 Series: * All versions before 21.4R3, * 22.2 versions before 22.2R3-S3.
CVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:N/R:
Affected products
1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
| Link | Tags |
|---|---|
| https://support.juniper.net/support/requesting-support/ | Vendor Advisory |
| https://supportportal.juniper.net/JSA103146 | Vendor Advisory |
| https://supportportal.juniper.net/s/article/EX-QFX-Procedure-to-format-install-QFX5K-device-using-a-USB | Technical Description |
Track CVE-2025-59957 inside VULONE
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2025-59957), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.
