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Junos SpaceApplication · Juniper

CVE-2026-21904

MEDIUM · 6.1 CVSS v3.1 Published 2026-04-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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
An Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability in Juniper Networks Junos Space allows an attacker to inject script tags in the list filter field that, when visited by another user, enables the attacker to execute commands with the target's permissions, including an administrator. This issue affects all versions of Junos Space before 24.1R5 Patch V3.

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 stored Cross-site Scripting (XSS) vulnerability in Juniper Networks Junos Space allows attackers to inject malicious script tags into the list filter field. When other users visit the affected page, the injected scripts execute with the victim's permissions, potentially enabling command execution with administrative privileges.

MitigationApply Junos Space version 24.1R5 Patch V3 or later to address the input validation failure in the list filter field.

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
Junos SpaceApplication
Affected:= 1.0= 1.1= 1.2= 1.3= 1.4= 2.0= 11.1= 11.2= 11.3= 11.4= 12.1= 12.2

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
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/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. Identify Junos Space version
    Log into the Junos Space web UI and navigate to the Administration > System > Platform menu, or run 'show version' via the CLI to obtain the installed software version
    Affected if The installed version matches 1.0, 1.1, 1.2, 1.3, 1.4, 2.0, 11.1, 11.2, 11.3, 11.4, 12.1, or 12.2
  2. Confirm list filter functionality is accessible
    Navigate to any page within Junos Space that contains a list filter input field (such as device lists, task lists, or report views)
    Affected if The list filter input field is present and usable in the web interface
  3. Verify user access to filtered views
    Check if any user accounts have permissions to view and interact with filtered list pages in the application
    Affected if Users have access to pages with list filter fields where injected scripts could be stored and executed

You are affected if your Junos Space version is 12.2 or earlier and users have access to the list filter functionality in the web interface.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Junos Space version 24.1R5 Patch V3 or later to address the input validation failure in the list filter field.

Recommended fix Moderate confidence

24.1R5 Patch V3

  1. 1. Identify the current Junos Space version by navigating to the Administration > System > Software menu in the web interface, or running 'show version' via CLI
  2. 2. Review the Juniper Networks Junos Space release notes at kb.juniper.net for version 24.1R5 Patch V3 to understand upgrade prerequisites
  3. 3. Schedule a maintenance window as upgrades require downtime
  4. 4. Take a complete backup of the Junos Space database and configuration
  5. 5. Download Junos Space version 24.1R5 Patch V3 from the Juniper Networks support portal
  6. 6. Upload the upgrade package to Junos Space via the web interface (Administration > System > Software > Upload) or CLI
  7. 7. Initiate the upgrade process and monitor for completion
  8. 8. After reboot, verify the new version is 24.1R5 Patch V3 using 'show version'
Caveat Ensure compatibility with managed devices and any custom scripts before upgrading; review Junos Space 24.1R5 release notes for any deprecated features or configuration changes

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

Fix this in Junos Space Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2026-21904 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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