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FirefoxWeb browser · Mozilla

CVE-2012-4214

HIGH · 9.3 CVSS v2.0 Published 2012-11-21
Fix available
A fix is available. Upgrade to 2.14 / 10.0.11 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click Patch available

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 nsTextEditorState::PrepareEditor function in Mozilla Firefox before 17.0, Firefox ESR 10.x before 10.0.11, Thunderbird before 17.0, Thunderbird ESR 10.x before 10.0.11, and SeaMonkey before 2.14 allows remote attackers to execute arbitrary code or cause a denial of service (heap memory corruption) via unspecified vectors, a different vulnerability than CVE-2012-5840.

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
How this class of weakness works · CWE-416

Memory is used after it has been freed, so its contents — now potentially attacker-controlled — drive the program's behaviour. With careful heap grooming this becomes code execution. The fix requires disciplined ownership of memory and often a targeted rework of the object lifecycle.

General guidance for the use after free class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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:< 17.0>= 10.0, < 10.0.11
Enterprise Linux DesktopOperating system
Affected:= 5.0= 6.0
Enterprise Linux EusOperating system
Affected:= 6.3
Enterprise Linux ServerOperating system
Affected:= 5.0= 6.0
Enterprise Linux WorkstationOperating system
Affected:= 5.0= 6.0
Ubuntu LinuxOperating system
Affected:= 10.04= 11.10= 12.04= 12.10
SeamonkeyApplication
Affected:< 2.14
ThunderbirdApplication
Affected:< 17.0

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
M
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete

AV:N/AC:M/Au:N/C:C/I:C/A:C

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 2.14 / 10.0.11 / 17.0 or later
Fixed in 2.1410.0.1117.0
Vendor patch bugzilla.mozilla.org →
Recommended fix High confidence

Firefox 17.0+ (or Firefox ESR 10.0.11+); Thunderbird 17.0+ (or Thunderbird ESR 10.0.11+); SeaMonkey 2.14+

  1. 1. Identify the installed Mozilla product (Firefox, Thunderbird, or SeaMonkey) and current version using 'firefox --version', 'thunderbird --version', or 'seamonkey --version'
  2. 2. For Firefox: Upgrade to version 17.0 or later (or Firefox ESR 10.0.11 or later if using the ESR channel)
  3. 3. For Thunderbird: Upgrade to version 17.0 or later (or Thunderbird ESR 10.0.11 or later if using the ESR channel)
  4. 4. For SeaMonkey: Upgrade to version 2.14 or later
  5. 5. Obtain the fixed version from the official Mozilla website (https://www.mozilla.org/) or from your Linux distribution's package repositories
  6. 6. Install the updated package using your system's package manager (e.g., 'yum update', 'apt-get install', or 'zypper update')
  7. 7. Restart the application and verify the new version is installed

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

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $3,200. Get the upgrade done

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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-2012-4214 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
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