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CVE-2025-59957VulnerabilityPublished

CVE-2025-59957: Juniper Networks Junos OS · Origin Validation Error

Affects Juniper Networks Junos OSSource CVE Database V5

0

Not known to be exploited · CVSS 6.8 Medium.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score
6.8Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Oct 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

What to do

Affected software

ProductAffectedFixed in
Juniper Networks Junos OSAffected
  • =0
  • =22.2
Fixed in–

AI-suggested

1. Immediately ensure that all Juniper EX4600 and QFX5000 Series devices are configured with strong root passwords to prevent unauthorized physical modification of configuration files. 2. Conduct integrity checks on the /etc/config/<platform>-defaults[-flex].conf file by comparing it against a clean version extracted from the original Junos OS image; coordinate with Juniper JTAC for extraction procedures. 3. Implement strict physical security controls to restrict unauthorized access to network devices, including locked cabinets and surveillance in data centers and network closets. 4. Regularly audit device configurations for unexpected or unauthorized changes, focusing on user accounts, IP addresses, and other critical settings. 5. Plan for and perform a full system reinstall from physical media if compromise is suspected to ensure complete removal of backdoors. 6. Monitor Juniper’s advisories for patches and apply updates to affected devices as soon as they become available. 7. Incorporate device configuration monitoring into security information and event management (SIEM) systems to detect anomalies promptly. 8. Train network operations staff to recognize signs of physical tampering and unusual device behavior.

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.

References

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