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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-40212

MEDIUM · 5.4 CVSS v3.1 Published 2026-04-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
58/100
Remediation priority · Elevated
Remotely reachable

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
OpenStack Skyline before 5.0.1, 6.0.0, and 7.0.0 has a DOM-based Cross-Site Scripting (XSS) vulnerability in the console because document.write is used unsafely, which is relevant in scenarios where administrators use the console web interface to view instance console logs.

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 · moderate confidence

OpenStack Skyline before versions 5.0.1, 6.0.0, and 7.0.0 contains a DOM-based XSS vulnerability in its console interface where unsanitized user input from instance console logs is rendered using the unsafe `document.write()` method, allowing script injection when administrators view console logs through the web interface.

MitigationUpgrade to a patched version (5.0.1, 6.0.0, 7.0.0 or later) that replaces `document.write()` with safe DOM manipulation methods, or avoid using the console web interface to view untrusted console logs until the patch is applied.

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

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
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:L/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 Skyline installation and version
    Query the Skyline API endpoint (e.g., GET /api/v1/versions) or check installed package version (e.g., `pip show skyline-console` or `rpm -q skyline-apiserver`). Compare against affected ranges: any version before 5.0.1, 6.0.0, or 7.0.0.
    Affected if Running a version of OpenStack Skyline earlier than 5.0.1, 6.0.0, or 7.0.0.
  2. Verify console web interface is enabled
    Check Skyline configuration files (typically in /etc/skyline or /etc/neutron/skyline) for console-related settings. Look for `enable_console` or similar flags, and confirm the console UI module is loaded in the web application.
    Affected if The console web interface feature is enabled in the Skyline configuration.
  3. Confirm admin access to console logs
    Check if administrative users have access to view instance console logs through the Skyline web UI. Verify role-based access controls allow console log viewing.
    Affected if Administrator users can access the console log viewing feature through the web interface.
  4. Inspect console template for document.write usage
    Examine frontend JavaScript files related to console rendering (typically in /usr/lib/python3.*/site-packages/skyline/console or similar frontend asset directories). Search for usage of `document.write()` in console log rendering logic.
    Affected if The console component uses `document.write()` to render console output without sanitization.

You are affected if running OpenStack Skyline before version 5.0.1/6.0.0/7.0.0 AND the console web interface is enabled and accessible to view instance console logs.

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

Upgrade to a patched version (5.0.1, 6.0.0, 7.0.0 or later) that replaces `document.write()` with safe DOM manipulation methods, or avoid using the console web interface to view untrusted console logs until the patch is applied.

Recommended fix High confidence

Upgrade to Skyline 5.0.1, 6.0.0, or 7.0.0 (whichever is the latest stable release in your supported branch)

  1. Identify the currently installed OpenStack Skyline version using the package manager or skyline version command
  2. Backup the current Skyline configuration and database
  3. Upgrade to Skyline version 5.0.1, 6.0.0, or 7.0.0 using the appropriate package manager (e.g., pip install skyline-console==5.0.1 or the distribution's package manager)
  4. Restart the Skyline services to apply the update
  5. Verify the upgrade was successful by checking the Skyline version
  6. Test the console functionality to confirm the document.write vulnerability is remediated
Caveat Review release notes for any configuration or API changes between versions; minor version upgrades typically have minimal breaking changes

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

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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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-2026-40212 in production — separate from our analysis above.

No notes yet

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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