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FirefoxWeb browser · Mozilla

CVE-2012-3964

HIGH · 10.0 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
Use-after-free vulnerability in the gfxTextRun::GetUserData 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 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via unspecified vectors.

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

Use-after-free vulnerability in Mozilla's gfxTextRun::GetUserData text rendering function allows remote attackers to execute arbitrary code via heap memory corruption. Affects Firefox < 15.0, Firefox ESR < 10.0.7, Thunderbird < 15.0, Thunderbird ESR < 10.0.7, and SeaMonkey < 2.12.

MitigationUpdate affected products to patched versions (Firefox 15.0+, Firefox ESR 10.0.7+, Thunderbird 15.0+, Thunderbird ESR 10.0.7+, SeaMonkey 2.12+) or later.

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:= 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
Thunderbird EsrApplication
Affected:= 10.0= 10.0.1= 10.0.2= 10.0.3= 10.0.4= 10.0.5= 10.0.6
ThunderbirdApplication
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= 1.5= 1.5.0.1
SeamonkeyApplication
Affected:<= 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= 2.0.10

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
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:L/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. Identify installed Mozilla product
    Check for presence of Firefox, Thunderbird, or SeaMonkey on the system. On Windows check Start menu or Program Files. On Linux check /usr/bin or package manager. On macOS check /Applications.
    Affected if Any of Firefox, Thunderbird, or SeaMonkey is installed
  2. Determine Firefox version
    Open Firefox, click Help > About Firefox, or run 'firefox --version' from command line, or check Windows registry HKLM\SOFTWARE\Mozilla\Mozilla Firefox\CurrentVersion
    Affected if Version is 10.0 through 10.0.6, or 14.0 or lower, or 1.0.x series (1.0, 1.0.1, 1.0.2, 1.0.3)
  3. Determine Thunderbird version
    Open Thunderbird, click Help > About Thunderbird, or run 'thunderbird --version' from command line, or check Windows registry HKLM\SOFTWARE\Mozilla\Mozilla Thunderbird\CurrentVersion
    Affected if Version is 10.0 through 10.0.6 (ESR), or 14.0 or lower, or 1.0.x through 1.0.8, or 1.5.x (1.5, 1.5.0.1)
  4. Determine SeaMonkey version
    Open SeaMonkey, click Help > About SeaMonkey, or run 'seamonkey --version' from command line
    Affected if Version is 2.11 or lower, or 2.0.x series (2.0 through 2.0.10)

The environment is affected if any of Firefox <= 14.0 (or 10.0.x), Thunderbird <= 14.0 (or 10.0.x ESR), or SeaMonkey <= 2.11 (or 2.0.x) is installed.

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

Update affected products to patched versions (Firefox 15.0+, Firefox ESR 10.0.7+, Thunderbird 15.0+, Thunderbird ESR 10.0.7+, SeaMonkey 2.12+) or later.

Recommended fix High confidence

Upgrade to Firefox 15.0+ (or Firefox ESR 10.0.7+), Thunderbird 15.0+ (or Thunderbird ESR 10.0.7+), or SeaMonkey 2.12+ as appropriate for your product line

  1. 1. Identify the affected Mozilla product (Firefox, Thunderbird, Thunderbird ESR, or SeaMonkey) currently installed in your environment.
  2. 2. Determine the current version of the installed product by checking About in the application menu or using the --version command-line flag.
  3. 3. For Firefox 10.0.x users: Upgrade to Firefox 15.0 or later.
  4. 4. For Firefox ESR 10.0.x users: Upgrade to Firefox ESR 10.0.7 or later (or migrate to a supported ESR branch).
  5. 5. For Thunderbird 10.0.x and earlier users: Upgrade to Thunderbird 15.0 or later.
  6. 6. For Thunderbird ESR 10.0.x users: Upgrade to Thunderbird ESR 10.0.7 or later.
  7. 7. For SeaMonkey 2.11 and earlier users: Upgrade to SeaMonkey 2.12 or later.
  8. 8. After upgrade, verify the version by checking About to confirm the fix is applied.
Caveat Minor: Ensure compatibility of existing extensions/add-ons with the new major version before deploying in production environments

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

Fix this in Firefox Scoped from the published advisory
  • Consultation0.5 h
  • Implementation0.5 h
  • Testing0.5 h
  • Review / QA0.5 h
2.0 hours of engineering $750
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Scan for this in your stack

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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-2012-3964 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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