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Wikipedia ToolbarApplication · Wikipedia

CVE-2009-4127

HIGH · 9.3 CVSS v2.0 Published 2009-12-02
Fix available
A fix is available. Upgrade to after 0.5.9.1 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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
Unspecified vulnerability in Wikipedia Toolbar extension before 0.5.9.2 for Firefox allows user-assisted remote attackers to execute arbitrary JavaScript with Chrome privileges via vectors involving unspecified Toolbar buttons and the eval function. NOTE: the provenance of this information is unknown; the details are obtained solely from third party information.

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

The Wikipedia Toolbar extension for Firefox before version 0.5.9.2 contains a JavaScript injection vulnerability where unspecified toolbar buttons use the eval function unsafely, allowing arbitrary JavaScript execution with Chrome (extension) privileges. This grants remote attackers elevated privileges beyond normal web page content, enabling potentially full compromise of the browser extension and user data.

MitigationUpgrade Wikipedia Toolbar to version 0.5.9.2 or later, which addresses the unsafe eval usage. If the extension is no longer maintained, consider removing it and using Wikipedia's official website features instead.

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
Wikipedia ToolbarApplication
Affected:<= 0.5.9.1= 0.2= 0.4= 0.4.1= 0.4.2= 0.4.4= 0.4.5= 0.4.6= 0.4.9= 0.5= 0.5.0.1= 0.5.0.2

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
M
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:M/Au:N/C:C/I:C/A:C

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. Confirm Wikipedia Toolbar is installed
    Open Firefox, click the menu button, select Add-ons and Themes, then look for 'Wikipedia Toolbar' in the Extensions list
    Affected if Wikipedia Toolbar appears in the installed extensions list
  2. Find the installed version number
    In the Firefox Add-ons Manager, click the gear icon or info button next to Wikipedia Toolbar to view its Details/Version information
    Affected if The displayed version is 0.5.9.1 or lower, or matches any of these: 0.2, 0.4, 0.4.1, 0.4.2, 0.4.4, 0.4.5, 0.4.6, 0.4.9, 0.5, 0.5.0.1, 0.5.0.2
  3. Locate extension files for manual version check
    Navigate to the Firefox profiles folder (typically in AppData\Roaming\Mozilla\Firefox\Profiles on Windows or ~/.mozilla/firefox on Linux/Mac), find the extension folder containing 'wikipedia' in the name, and check install.rdf or manifest.json for the version value
    Affected if The version field in the extension manifest is 0.5.9.1 or lower, or matches any affected version listed above
  4. Verify the extension is active
    In Firefox Add-ons Manager, confirm the Wikipedia Toolbar shows as Enabled rather than Disabled
    Affected if The toolbar extension is enabled and the version is in the affected list

You are affected if Wikipedia Toolbar is installed, enabled, and its version is 0.5.9.1 or lower, or exactly matches any of the specific affected versions (0.2, 0.4, 0.4.1, 0.4.2, 0.4.4, 0.4.5, 0.4.6, 0.4.9, 0.5, 0.5.0.1, 0.5.0.2).

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 a release after 0.5.9.1
Interim mitigation

Upgrade Wikipedia Toolbar to version 0.5.9.2 or later, which addresses the unsafe eval usage. If the extension is no longer maintained, consider removing it and using Wikipedia's official website features instead.

Recommended fix High confidence

Wikipedia Toolbar version 0.5.9.2 or later

  1. Open Firefox and navigate to the Add-ons manager (Tools > Add-ons or about:addons)
  2. Locate the Wikipedia Toolbar extension in the list of installed extensions
  3. Check the current version - if it is 0.5.9.1 or earlier, an update is needed
  4. Update the Wikipedia Toolbar extension to version 0.5.9.2 or later through the Add-ons manager's update feature
  5. Restart Firefox to ensure the updated extension is fully loaded
Caveat Standard patch update; minimal risk as this is a security fix release

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

Fix this in Wikipedia Toolbar Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.

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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-2009-4127 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