Juniper Junos OS URL Filtering Bypass (before 25.4R2-S1)
CVE-2026-57054 Published on July 9, 2026
Junos OS: MX Series: Web filtering doesn't block specifically formatted URLs
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.
Vulnerability Analysis
CVE-2026-57054 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, with no impact on integrity, and no impact on availability.
Weakness Type
Use of Incorrectly-Resolved Name or Reference
The software uses a name or reference to access a resource, but the name/reference resolves to a resource that is outside of the intended control sphere.
Products Associated with CVE-2026-57054
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Affected Versions
Juniper Networks Junos OS:- Before 23.2R2-S7 is affected.
- Version 23.4 and below 23.4R2-S8 is affected.
- Version 24.2 and below 24.2R2-S5 is affected.
- Version 24.4 and below 24.4R2-S4 is affected.
- Version 25.2 and below 25.2R2-S1 is affected.
- Version 25.4 and below 25.4R1-S2, 25.4R2 is affected.