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FirefoxWeb browser · Mozilla

CVE-2012-0459

HIGH · 7.5 CVSS v2.0 Published 2012-03-14
Fix available
A fix is available. Upgrade to after 2.7 or later.
See remediation →
84/100
Remediation priority · High
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
The Cascading Style Sheets (CSS) implementation in Mozilla Firefox 4.x through 10.0, Firefox ESR 10.x before 10.0.3, Thunderbird 5.0 through 10.0, Thunderbird ESR 10.x before 10.0.3, and SeaMonkey before 2.8 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via dynamic modification of a keyframe followed by access to the cssText of the keyframe.

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

Memory corruption vulnerability in Mozilla's CSS implementation where dynamic modification of a keyframe followed by access to its cssText property causes either application crash (DoS) or potential arbitrary code execution. The vulnerability stems from improper handling of keyframe manipulation in the CSS rendering engine.

MitigationApply vendor-supplied updates: Firefox ESR 10.x to 10.0.3 or later, Thunderbird ESR 10.x to 10.0.3 or later, SeaMonkey to 2.8 or later. Until patched, restrict access to untrusted web content where possible.

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:= 4.0= 4.0.1= 5.0= 5.0.1= 6.0= 6.0.1= 6.0.2= 7.0= 7.0.1= 8.0= 8.0.1= 9.0
Firefox EsrWeb browser
Affected:= 10.1= 10.2
ThunderbirdApplication
Affected:= 5.0= 6.0= 6.0.1= 6.0.2= 7.0= 7.0.1= 8.0= 9.0= 9.0.1
Thunderbird EsrApplication
Affected:= 10.0= 10.0.1= 10.0.2
SeamonkeyApplication
Affected:<= 2.7= 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

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
Low
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:L/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify installed Mozilla product and version
    For Firefox: go to Help > About Firefox. For Thunderbird: go to Help > About Thunderbird. For SeaMonkey: go to Help > About SeaMonkey. Note the exact version number displayed.
    Affected if The version matches any of the following: Firefox 4.0-9.0.1, Firefox ESR 10.1-10.2, Thunderbird 5.0-9.0.1, Thunderbird ESR 10.0-10.0.2, SeaMonkey 1.0-1.9 or SeaMonkey 2.0-2.7
  2. Confirm product type and platform
    Identify whether the affected installation is Firefox, Thunderbird, or SeaMonkey, and note whether it is the ESR (Extended Support Release) branch or standard release.
    Affected if The product is any of Firefox, Thunderbird, or SeaMonkey and falls within the affected version ranges listed in the CVE
  3. Verify CSS keyframe functionality is accessible
    This vulnerability is triggered through web content manipulating CSS keyframes via JavaScript (e.g., modifying a keyframe rule and accessing its cssText property). Confirm the browser has JavaScript enabled and can render web content.
    Affected if JavaScript is enabled and the application can process CSS keyframe rules, which is the default configuration for all affected versions

A user is affected if they are running any of the listed Firefox, Thunderbird, or SeaMonkey versions (4.0-9.0.x for Firefox, 5.0-9.0.x for Thunderbird, 1.x or 2.x up to 2.7 for SeaMonkey, or ESR 10.x versions 10.0-10.2) and use the application to render web content with JavaScript enabled.

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.

From vendor data
Upgrade available Upgrade to a release after 2.7
Interim mitigation

Apply vendor-supplied updates: Firefox ESR 10.x to 10.0.3 or later, Thunderbird ESR 10.x to 10.0.3 or later, SeaMonkey to 2.8 or later. Until patched, restrict access to untrusted web content where possible.

Fix this in Firefox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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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-2012-0459 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