FirefoxWeb browser · Mozilla
CVE-2012-3978
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 · uneditedThe nsLocation::CheckURL function in Mozilla Firefox before 15.0, Firefox ESR 10.x before 10.0.7, Thunderbird before 15.0, Thunderbird ESR 10.x before 10.0.7, and SeaMonkey before 2.12 does not properly follow the security model of the location object, which allows remote attackers to bypass intended content-loading restrictions or possibly have unspecified other impact via vectors involving chrome code.
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 confidenceThe nsLocation::CheckURL function in multiple Mozilla products (Firefox, Thunderbird, SeaMonkey) fails to properly enforce the security model for the location object, allowing remote attackers to bypass content-loading restrictions by exploiting chrome code pathways.
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
= 10.0= 10.0.1= 10.0.2= 10.0.3= 10.0.4= 10.0.5= 10.0.6<= 14.0= 1.0= 1.0.1= 1.0.2= 1.0.3= 10.0= 10.0.1= 10.0.2= 10.0.3= 10.0.4= 10.0.5= 10.0.6<= 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= 1.5= 1.5.0.1<= 2.11= 2.0= 2.0.1= 2.0.2= 2.0.3= 2.0.4= 2.0.5= 2.0.6= 2.0.7= 2.0.8= 2.0.9= 2.0.10CVSS 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
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:M/Au:N/C:P/I:P/A:P
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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Identify installed Mozilla productCheck which Mozilla application is installed: Firefox, Thunderbird, or SeaMonkey. On Windows check Start menu or Programs and Features. On Linux check package manager or look for application launchers.Affected if Any of Firefox, Thunderbird, or SeaMonkey is installed
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Determine Firefox versionFor Firefox: Type 'about:support' in the address bar or go to Help > About Firefox. The version number is displayed at the top.Affected if Version is 10.0 through 10.0.6, or up to 14.0, or 1.0 through 1.0.3
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Determine Thunderbird versionFor Thunderbird: Go to Help > About Thunderbird. The version number is displayed in the dialog window.Affected if Version is 10.0 through 10.0.6 (ESR), or up to 14.0, or 1.0 through 1.0.8, or 1.5/1.5.0.1
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Determine SeaMonkey versionFor SeaMonkey: Go to Help > About SeaMonkey. The version number is displayed in the dialog window.Affected if Version is 2.0 through 2.0.10, or up to 2.11
A user is affected if they have Firefox 10.0-10.0.6, 1.0-1.0.3, or up to 14.0; Thunderbird 10.0-10.0.6, 1.0-1.0.8, 1.5, or up to 14.0; or SeaMonkey 2.0-2.0.10 or up to 2.11 installed.
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 15.0+, Thunderbird 15.0+, SeaMonkey 2.12+, or Firefox/Thunderbird ESR 10.0.7+ to patch the vulnerable nsLocation::CheckURL function.
Fix this in Firefox
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 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 $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2012-3978 — 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-2012-3978 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