FirefoxWeb browser · Mozilla

CVE-2012-1953

HIGH · 9.3 CVSS v2.0 Published 2012-07-18

Fix available

A fix is available. Upgrade to after 2.10 or later.

See remediation →

100/100

Remediation priority · Urgent

Remotely reachable No privileges Zero-click

Official description

NVD · unedited

The ElementAnimations::EnsureStyleRuleFor function in Mozilla Firefox 4.x through 13.0, Firefox ESR 10.x before 10.0.6, Thunderbird 5.0 through 13.0, Thunderbird ESR 10.x before 10.0.6, and SeaMonkey before 2.11 allows remote attackers to cause a denial of service (buffer over-read, incorrect pointer dereference, and heap-based buffer overflow) or possibly execute arbitrary code via a crafted web site.

Technical summary

dbcve analysis · high confidence

Heap buffer overflow and pointer dereference errors in the ElementAnimations::EnsureStyleRuleFor function in Mozilla's layout/style engine allow crafted CSS animations on web pages to trigger memory corruption, potentially enabling arbitrary code execution.

MitigationApply vendor patches: update Firefox to 14.0+/ESR 10.0.6+, Thunderbird to 14.0+/ESR 10.0.6+, or SeaMonkey to 2.11+. This is a client-side vulnerability; ensure all end-user systems are patched.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions

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

ThunderbirdApplication

Affected:= 5.0= 6.0= 6.0.1= 6.0.2= 7.0= 7.0.1= 8.0= 9.0= 9.0.1= 10.0= 10.0.1= 10.0.2

Thunderbird EsrApplication

Affected:= 10.0= 10.0.1= 10.0.2= 10.0.3= 10.0.4= 10.0.5

SeamonkeyApplication

Affected:<= 2.10= 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

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?

dbcve checks

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

Identify the installed Mozilla product

Check which Mozilla application is installed: Firefox (browser), Thunderbird (email client), or SeaMonkey (suite). On Windows check Program Files folder or Add/Remove Programs. On Linux check /usr/bin or package manager. On macOS check Applications folder.

Affected if The system has any of the affected products installed (Firefox, Thunderbird, or SeaMonkey)
Determine the exact version number

For Firefox: go to Help > About Firefox or run 'firefox --version'. For Thunderbird: go to Help > About Thunderbird or run 'thunderbird --version'. For SeaMonkey: go to Help > About SeaMonkey or run 'seamonkey --version'.

Affected if The installed version matches any of the affected versions listed in the CVE advisory
Verify CSS animations are in use

This vulnerability is triggered through crafted CSS animations on web pages. Check if the browser frequently visits untrusted websites or has extensions that inject CSS. The flaw exists in the ElementAnimations::EnsureStyleRuleFor function in the layout/style engine.

Affected if The affected browser version is running and capable of rendering web content with CSS animations
Confirm the vulnerability is exploitable in this context

The vulnerability requires the layout/style engine to process CSS animations. Any web page with malicious CSS animation code could trigger it. This is a client-side flaw affecting the application itself, not a server configuration.

Affected if The affected product version is running and web content can be rendered

A system is affected if it runs any of the listed Firefox versions (4.0 through 9.0), Thunderbird versions (5.0 through 10.0.2), Thunderbird ESR (10.0 through 10.0.5), or SeaMonkey (2.10 or lower, or any 1.x version), as these all contain the vulnerable ElementAnimations::EnsureStyleRuleFor function in their layout/style engine.

Generated from the published advisory. Verify against your own configuration.

Remediation

dbcve · scoped

Upgrade available Upgrade to a release after 2.10

Interim mitigation

Apply vendor patches: update Firefox to 14.0+/ESR 10.0.6+, Thunderbird to 14.0+/ESR 10.0.6+, or SeaMonkey to 2.11+. This is a client-side vulnerability; ensure all end-user systems are patched.

Recommended fix High confidence

Firefox 13.0 or later (or Firefox ESR 10.0.6+); Thunderbird 13.0 or later (or Thunderbird ESR 10.0.6+); SeaMonkey 2.11 or later

1. Close all instances of the affected Mozilla product (Firefox, Thunderbird, or SeaMonkey).
2. Back up bookmarks, passwords, and important data if migrating between major versions.
3. Download the latest stable release from the official Mozilla website (https://www.mozilla.org/) or use your system's package manager.
4. Install the new version over the existing installation, or uninstall the old version first before installing the new one.
5. Restart the application after installation completes.
6. Verify the installed version by checking Help > About (Firefox/Thunderbird) or Help > About SeaMonkey.

Caveat Upgrading across major version jumps may require profile migration; some older extensions/add-ons may be incompatible with newer versions

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

Fix this in Firefox Scoped from the published advisory

Consultation1.0 h
Testing2.0 h
Review / QA1.0 h

4.0 hours of engineering $750

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Scan for this in your stack

Free · runs locally

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References

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2012-1953 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2012-1953?

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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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

At a glance

A fix existsUpgrade to after 2.10 or later

Severity 9.3 High

Exploit likelihood EPSS, next 30 days 4.3%

Affects: Firefox

Remediation

A high-priority fix

Fix this in Firefox 4 hrs · Low

Typical engagement from $750

Get a fix See the full breakdown ↓

A high-priority vulnerability. Send your environment and a specialist will scope CVE-2012-1953 and return a fixed quote and timeline.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

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.

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.

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.

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.

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.

Check your environment

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.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Am I affected?

Remediation

References