CVE-2025-59957

MEDIUM
Published Oct 9, 2025 Modified Jan 23, 2026 CWE-346

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.

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CVSS v3.1 Score

6.8
MEDIUM
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-346 CWE-346

Affected Products

Vendor Product
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper junos
juniper ex4600
juniper ex4650
juniper qfx5110
juniper qfx5120
juniper qfx5130
juniper qfx5200
juniper qfx5210
juniper qfx5220
juniper qfx5230-64cd
juniper qfx5240
juniper qfx5241
juniper qfx5700

References

Frequently Asked Questions

What is CVE-2025-59957? +
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. It has a CVSS v3.1 base score of 6.8 (MEDIUM).
How severe is CVE-2025-59957? +
CVE-2025-59957 has a CVSS v3.1 score of 6.8 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.
What products are affected by CVE-2025-59957? +
CVE-2025-59957 affects products from juniper, specifically: ex4600, ex4650, junos, qfx5110, qfx5120, qfx5130, qfx5200, qfx5210, qfx5220, qfx5230-64cd, qfx5240, qfx5241, qfx5700. Check the affected products table above for specific version ranges.
How do I check if I'm vulnerable to CVE-2025-59957? +
You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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