CVE-2025-30661

7.3 HIGH

📋 TL;DR

A local privilege escalation vulnerability in Juniper Junos OS allows low-privileged users to place scripts that execute as root during system boot on specific line cards. This could give attackers complete control of affected routers and switches. Only users with local file system access on MPC10, MPC11, LC4800, LC9600, MX304-LMIC16, SRX4700, and EX9200-15C line cards running vulnerable Junos versions are affected.

💻 Affected Systems

Products:

• Juniper Networks Junos OS

Versions: 23.2 before 23.2R2-S4, 23.4 before 23.4R2-S5, 24.2 before 24.2R2-S1, 24.4 before 24.4R1-S3, 24.4R2

Operating Systems: Junos OS

Default Config Vulnerable: ⚠️ Yes

Notes: Only affects specific line cards: MPC10, MPC11, LC4800, LC9600, MX304-LMIC16, SRX4700, EX9200-15C. Versions prior to 23.1R2 are not affected.

📦 What is this software?

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

Junos by Juniper

Junos OS is Juniper Networks' flagship network operating system running on enterprise routers, switches, security appliances, and data center infrastructure worldwide. Deployed across telecommunications providers, ISPs, cloud service providers, financial institutions, and large enterprises, Junos po...

Learn more about Junos →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system compromise with root-level access, enabling persistent backdoors, data exfiltration, network manipulation, and lateral movement to other systems.

🟠

Likely Case

Privilege escalation from low-privileged user to root, allowing configuration changes, service disruption, and credential harvesting.

🟢

If Mitigated

Limited impact if proper access controls prevent local user access to vulnerable line cards and file systems.

🌐 Internet-Facing: LOW - Requires local access to affected line cards, not remotely exploitable.

🏢 Internal Only: HIGH - Local attackers or compromised accounts can exploit this to gain root privileges on critical network infrastructure.

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ✅ No

Complexity: LOW

Requires local access and low-privileged user account. Exploitation involves copying scripts to specific locations that execute during boot.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 23.2R2-S4, 23.4R2-S5, 24.2R2-S1, 24.4R1-S3 (or later)

Vendor Advisory: https://supportportal.juniper.net/JSA100057

Restart Required: Yes

Instructions:

1. Identify affected line cards and Junos versions. 2. Download appropriate fixed version from Juniper support portal. 3. Backup configuration. 4. Install update following Juniper upgrade procedures. 5. Reboot affected devices.

🔧 Temporary Workarounds

Restrict local user access

all

Limit local user accounts and file system access to affected line cards

Copy

configure
set system login user [username] class read-only
commit

Monitor file system changes

all

Implement file integrity monitoring on script directories

🧯 If You Can't Patch

• Implement strict access controls to prevent unauthorized local access to affected line cards
• Deploy network segmentation to isolate vulnerable devices and monitor for suspicious activity

🔍 How to Verify

Check if Vulnerable:

Copy

Check Junos version with 'show version' and verify if running affected version on listed line cards

Check Version:

Copy

show version

Verify Fix Applied:

Copy

Verify Junos version is patched with 'show version' and check line card models

📡 Detection & Monitoring

Log Indicators:

• Unauthorized file modifications in script directories
• Unexpected privilege escalation events
• Suspicious boot-time script execution

Network Indicators:

• Unusual configuration changes
• Unexpected administrative access patterns

SIEM Query:

Copy

source="junos" AND (event_type="file_modification" OR event_type="privilege_escalation")

📊 Metadata

CVE ID: CVE-2025-30661

CVSS v3 Score: 7.3 (HIGH)

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

CWE: CWE-732

EPSS Score: 0.02% exploit probability (2.6th percentile)

Published: July 11, 2025

Last Updated: January 26, 2026

🔗 References

• https://github.com/orangecertcc/security-research/security/advisories/GHSA-2p66-9j7x-fmch Third Party Advisory
• https://supportportal.juniper.net/JSA100057 Vendor Advisory

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