CVE-2026-57054

Junos OS: MX Series: Web filtering doesn't block specifically formatted URLs

Published Jul 9, 2026 CVSS 4.0 · 6.9 Medium EPSS < 1% KEV · Not listed
Description
A Use of Incorrectly-Resolved Name or Reference vulnerability in the URL filtering plugin of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass web filtering and access downstream resources that should be unreachable.



If an MX Series device is configured with web filtering, and an attacker sends a request with a specifically formatted URL, this request will get forwarded despite the system being configured to block it. In turn, an attacker can access downstream resources that are expected to be unreachable.

This issue affects Junos OS on MX Series:


* all versions before 23.2R2-S7,
* 23.4 versions before 23.4R2-S8,
* 24.2 versions before 24.2R2-S5,
* 24.4 versions before 24.4R2-S4,
* 25.2 versions before 25.2R2-S1,
* 25.4 versions before 25.4R1-S2, 25.4R2.

Remediation

Vendor Solution

The following software releases have been updated to resolve this specific issue: Junos OS: 23.2R2-S7, 23.4R2-S8, 24.2R2-S5, 24.4R2-S4, 25.2R2-S1, 25.4R1-S2, 25.4R2, 26.2R1, and all subsequent releases.


Vendor Workaround

There are no known workarounds for this issue.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Juniper Networks
Juniper Networks junos Os
Vendors & Products Juniper Networks
Juniper Networks junos Os
Type Values Removed Values Added
Description A Use of Incorrectly-Resolved Name or Reference vulnerability in the URL filtering plugin of Juniper Networks Junos OS on MX Series allows an unauthenticated, network-based attacker to bypass web filtering and access downstream resources that should be unreachable. If an MX Series device is configured with web filtering, and an attacker sends a request with a specifically formatted URL, this request will get forwarded despite the system being configured to block it. In turn, an attacker can access downstream resources that are expected to be unreachable. This issue affects Junos OS on MX Series: * all versions before 23.2R2-S7, * 23.4 versions before 23.4R2-S8, * 24.2 versions before 24.2R2-S5, * 24.4 versions before 24.4R2-S4, * 25.2 versions before 25.2R2-S1, * 25.4 versions before 25.4R1-S2, 25.4R2.
Title Junos OS: MX Series: Web filtering doesn't block specifically formatted URLs
Weaknesses CWE-706
References
Metrics cvssV3_1

{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N'}

cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/AU:Y/RE:M'}