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JunosOperating system · Juniper

CVE-2026-57054

MEDIUM · 5.8 CVSS v3.1 Published 2026-07-09
Fix available
A fix is available. Upgrade to 23.2 or later.
See remediation →
67/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click 6 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

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 by sending a specifically formatted URL. This causes blocked requests to be forwarded to downstream resources that should be unreachable, effectively circumventing the intended security policy.

MitigationApply the vendor-supplied Junos OS updates: upgrade to 23.2R2-S7 or later, 23.4R2-S8 or later, 24.2R2-S5 or later, 24.4R2-S4 or later, 25.2R2-S1 or later, or 25.4R1-S2/25.4R2 or later. Until patches are applied, implement additional network-level filtering or segmentation as a compensating control.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
JunosOperating system
Affected:< 23.2= 23.2= 23.4= 24.2= 24.4= 25.2= 25.4

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify device is MX Series
    Run 'show chassis hardware' or 'show system information' to confirm the device model is MX-series
    Affected if Device is not an MX Series router - this vulnerability only affects MX Series
  2. Check Junos OS version
    Run 'show version' to obtain the installed Junos OS version
    Affected if Version is < 23.2, or equals 23.2, 23.4, 24.2, 24.4, 25.2, or 25.4 (any of the affected versions listed)
  3. Confirm URL filtering is enabled
    Run 'show services url-filter status' or check the URL filtering configuration with 'show configuration | display set | match url-filter'
    Affected if URL filtering is not configured or enabled - the vulnerability only applies when URL filtering policy is active

The device is affected if it is an MX Series router running a vulnerable Junos OS version (23.2, 23.4, 24.2, 24.4, 25.2, 25.4 or any version below 23.2) AND has URL filtering enabled.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 23.2 or later
Fixed in 23.2
Interim mitigation

Apply the vendor-supplied Junos OS updates: upgrade to 23.2R2-S7 or later, 23.4R2-S8 or later, 24.2R2-S5 or later, 24.4R2-S4 or later, 25.2R2-S1 or later, or 25.4R1-S2/25.4R2 or later. Until patches are applied, implement additional network-level filtering or segmentation as a compensating control.

Recommended fix High confidence

23.2R2-S7 / 23.4R2-S8 / 24.2R2-S5 / 24.4R2-S4 / 25.2R2-S1 / 25.4R1-S2 or later (depending on which release branch you are on)

  1. 1. Identify the current Junos OS version on the MX Series device using 'show version'
  2. 2. Review the current web filtering configuration with 'show configuration | display set | match web-filter'
  3. 3. Based on current version, upgrade to one of the fixed releases: 23.2R2-S7, 23.4R2-S8, 24.2R2-S5, 24.4R2-S4, 25.2R2-S1, or 25.4R1-S2/25.4R2
  4. 4. After upgrade, verify web filtering functionality is operational with 'show web-filter statistics'
  5. 5. Test that URL filtering is properly blocking requests that should be blocked
Caveat Standard Junos upgrade best practices apply - review release notes for any compatibility concerns and schedule maintenance window

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Junos Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-57054 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data