CVE-2025-59957

Persistent system takeover via unprotected defaults file

Published Oct 9, 2025 · Updated Oct 9, 2025

Origin validation error in Junos OS on EX4600 and QFX5000 switches allows physically proximate attackers to gain complete system control. When no root password is configured, the system imports attacker-written statements from the platform-defaults or platform-defaults-flex file under /etc/config without displaying them to the operator. Physical access to a switch running any version before 21.4R3 or a 22.2 version before 22.2R3-S3 is required; injected users, IP addresses, and other settings persist across reboots and zeroization.

CVSS severity6.8
Medium
EPSS probability0.19%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Origin validation error in Junos OS on EX4600 and QFX5000 switches allows physically proximate attackers to gain complete system control. When no root password is configured, the system imports attacker-written statements from the platform-defaults or platform-defaults-flex file under /etc/config without displaying them to the operator. Physical access to a switch running any version before 21.4R3 or a 22.2 version before 22.2R3-S3 is required; injected users, IP addresses, and other settings persist across reboots and zeroization.

The record

CVE
CVE-2025-59957
Published
Oct 9, 2025
Updated
Oct 9, 2025
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-346, T1565.001
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 9, 2025CVE publishedPublication date reported by the CVE source.
  2. Oct 9, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <21.4R3
  2. Affected versionversion=22.2 <22.2R3-S3

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=0 <21.4R3; version=22.2 <22.2R3-S3

Published CVSS scores

7.0Juniper NetworksCVSS:4.0/AV:P/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
6.8Juniper NetworksCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-346Origin Validation Error
T1565.001Stored Data Manipulation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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