FirefoxWeb browser · Mozilla
CVE-2011-2986
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 · uneditedMozilla Firefox 4.x through 5, Thunderbird before 6, SeaMonkey 2.x before 2.3, and possibly other products, when the Direct2D (aka D2D) API is used on Windows, allows remote attackers to bypass the Same Origin Policy, and obtain sensitive image data from a different domain, by inserting this data into a canvas.
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 Direct2D (D2D) API implementation in Mozilla Firefox 4.x-5, Thunderbird before 6, and SeaMonkey before 2.3 on Windows contains a Same Origin Policy bypass. Attackers can inject data from a different domain into a canvas element and then extract that cross-origin image data, violating the browser's security boundary.
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
= 4.0= 4.0.1= 5.0<= 5.0= 0.1= 0.2= 0.3= 0.4= 0.5= 0.6= 0.7= 0.7.1= 0.7.2= 0.7.3= 0.8= 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= 1.0.9= 1.1= 1.1.1CVSS 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
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- None
- Availability
- None
AV:N/AC:L/Au:N/C:P/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify the installed Firefox versionOpen Firefox, click Help > About Firefox, or navigate to about:support and locate the Version fieldAffected if Version is 4.0, 4.0.1, or 5.0 (any version from 4.x through 5.0)
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Identify the installed Thunderbird versionOpen Thunderbird, click Help > About Thunderbird and note the version numberAffected if Version is 5.0 or lower, or falls in the 0.x to 0.8 range
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Identify the installed SeaMonkey versionOpen SeaMonkey, click Help > About SeaMonkey and note the version numberAffected if Version is between 1.0 and 1.1.1 inclusive
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Confirm the operating system is WindowsCheck the OS running the browser (this vulnerability only affects Windows via Direct2D API)Affected if The browser is running on any Windows version - the flaw does not exist on Linux or macOS
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Check if Direct2D/hardware acceleration is enabledIn Firefox: type about:config in address bar, search for 'direct2d' or 'hardware_acceleration' and check the value. In Thunderbird/SeaMonkey: check Tools > Options > Advanced > General for hardware acceleration checkboxAffected if Hardware acceleration or Direct2D rendering is turned ON - this must be enabled for the flaw to apply
You are affected if you run any of the listed Firefox (4.0-5.0), Thunderbird (0.x-5.0), or SeaMonkey (1.0-1.1.1) versions on Windows with hardware acceleration/Direct2D enabled.
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 dataUpgrade affected products to Firefox 6+, Thunderbird 6+, or SeaMonkey 2.3+, which contain the patched D2D handling. Alternatively, disable hardware acceleration/Direct2D in browser settings as a workaround.
Fix this in Firefox
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 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 $1,424.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2011-2986 — 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-2011-2986 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
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