Vulnerability in Juniper EX4600 Series (CVE-2025-59957)
Summary
Vulnerability in Juniper EX4600 Series (CVE-2025-59957). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
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/-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.
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2025-59957 has been found in Juniper EX4600 Series.
Successful exploitation can lead to full system takeover. CVSS score: 6.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Juniper EX4600 Series CVE-2025-59957" on the vendor's site.
CVE-2025-59957 (Juniper EX4600 Series) — CWE-346 / CVSS v3 6.8
Attack vector: physical / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-346) exists in Juniper EX4600 Series.
Check the vendor advisory for the affected versions of Juniper EX4600 Series.
Severity: Medium (CVSS 6.8/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Juniper EX4600 Series を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- patch sirt@juniper.net
- patch sirt@juniper.net
- web sirt@juniper.net