FirefoxWeb browser · Mozilla
CVE-2012-4206
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 · uneditedUntrusted search path vulnerability in the installer in Mozilla Firefox before 17.0 and Firefox ESR 10.x before 10.0.11 on Windows allows local users to gain privileges via a Trojan horse DLL in the default downloads directory.
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 confidenceUntrusted search path (DLL hijacking) vulnerability in the Firefox Windows installer. The installer loads DLLs from the default downloads directory (user-writable) before system directories, allowing a local attacker to place a malicious DLL that executes with elevated privileges during installation.
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
FirefoxWeb browser
<= 16.0.2= 0.1= 0.2= 0.3= 0.4= 0.5= 0.6= 0.6.1= 0.7= 0.7.1= 0.8= 0.9CVSS 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
- Local
- Complexity
- M
- Authentication
- None
- Confidentiality
- Complete
- Integrity
- Complete
- Availability
- Complete
AV:L/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 checksWork through these to decide whether this CVE applies to you.
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Check installed Firefox versionOpen Firefox, go to Help > About Firefox, or check Registry at HKEY_LOCAL_MACHINE\SOFTWARE\Mozilla\Mozilla Firefox\CurrentVersionAffected if The installed version is 16.0.2 or earlier, or one of the specific older versions (0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.6.1, 0.7, 0.7.1, 0.8, 0.9)
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Verify Windows installer was usedCheck if Firefox was installed on Windows (not portable/macOS) by looking for installation files in Program Files or Program Files (x86)\Mozilla FirefoxAffected if Firefox was installed on Windows using the vulnerable installer package
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Inspect downloads directory permissionsRight-click the default downloads folder (typically C:\Users\<username>\Downloads), select Properties > Security, and check if other users or groups have Write or Modify permissionsAffected if The downloads directory grants Write or Modify permissions to other local users or groups (non-admin users besides the owner)
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Check for recent installation activityReview Windows Event Viewer under Windows Logs > Application for Mozilla Firefox installer events, or check %TEMP% for installer log filesAffected if A vulnerable Firefox installer (version <=16.0.2 or 0.x series) was recently executed on the system
You are affected if Firefox was installed on Windows using a vulnerable installer version (16.0.2 or earlier, or 0.x series) AND the downloads directory is writable by other local users who could place a malicious DLL.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpdate to Firefox 17.0+ or Firefox ESR 10.0.11+ to patch the vulnerable installer. Ensure the downloads directory is not shared or writable by other local users.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 h
- Implementation1.0 h
- Testing1.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-4206 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2012-4206 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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