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FirefoxWeb browser · Mozilla

CVE-2012-3965

HIGH · 9.3 CVSS v2.0 Published 2012-08-29
Fix available
A fix is available. Upgrade to after 14.0 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
Mozilla Firefox before 15.0 does not properly restrict navigation to the about:newtab page, which allows remote attackers to execute arbitrary JavaScript code with chrome privileges via a crafted web site that triggers creation of a new tab and then a new window.

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

Mozilla Firefox before 15.0 contains a vulnerability in how it restricts navigation to the about:newtab page. A malicious website can trigger creation of a new tab followed by a new window in a way that allows the attacker to execute arbitrary JavaScript code with chrome privileges (full browser privileges outside the web content sandbox).

MitigationUpgrade to Firefox 15.0 or later which contains the fix for this vulnerability. Organizations should ensure automated browser updates are enabled or deploy the patched version through their patch management systems.

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
Affected:<= 14.0= 1.0= 1.0.1= 1.0.2= 1.0.3= 1.0.4= 1.0.5= 1.0.6= 1.0.7= 1.0.8= 1.4.1= 1.5

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. Check if Firefox is installed
    Open a terminal or command prompt and run: firefox --version (Linux/macOS) or check Programs and Features in Windows. Alternatively, navigate to Firefox and look at Help > About Firefox
    Affected if Firefox is not installed or cannot be determined - the system is not affected
  2. Determine the installed Firefox version number
    In Firefox, go to Help > About Firefox, or run 'firefox --version' from command line. Note the full version number (e.g., 14.0, 13.0, 1.5)
    Affected if Cannot determine version - status unknown
  3. Compare installed version to affected range
    Check if the installed version is less than 15.0. Affected versions include: any version <= 14.0, or specifically 1.0 through 1.0.8, 1.4.1, and 1.5
    Affected if Installed version is less than 15.0 - the environment IS affected by this vulnerability
  4. Verify patch level if version appears to be 14.x
    If version shows as 14.0.x, check if update has been applied. In Help > About Firefox, look for 'You are running a vulnerable version of Firefox' notification, or check the actual version string includes 14.0.x updates
    Affected if Running any Firefox version below 15.0 - the vulnerability is present

A system is affected if it runs any version of Mozilla Firefox below 15.0, as the vulnerability exists in the about:newtab page navigation restriction for all those versions.

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 14.0
Interim mitigation

Upgrade to Firefox 15.0 or later which contains the fix for this vulnerability. Organizations should ensure automated browser updates are enabled or deploy the patched version through their patch management systems.

Recommended fix High confidence

Firefox 15.0 or later (recommended: latest stable release)

  1. 1. Check current Firefox version by navigating to Help > About Firefox
  2. 2. If Firefox version is 14.0 or earlier, upgrade to the latest stable Firefox release
  3. 3. Download the latest version from https://www.mozilla.org/firefox/ or use the built-in update mechanism
  4. 4. After upgrade, verify the version is 15.0 or later to confirm the vulnerability is patched
  5. 5. Alternatively, use your system's package manager to update Firefox (e.g., apt-get update && apt-get upgrade firefox on Ubuntu/Debian)
Caveat Minor: Some older Firefox extensions/add-ons may be incompatible with newer versions; review add-on compatibility before upgrading

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

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing1.0 h
  • Review / QA1.0 h
4.0 hours of engineering $750
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,200.

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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-2012-3965 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