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FirefoxWeb browser · Mozilla

CVE-2012-3957

HIGH · 10.0 CVSS v2.0 Published 2012-08-29
Fix available
A fix is available. Upgrade to 2.12 / 10.0.7 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
Heap-based buffer overflow in the nsBlockFrame::MarkLineDirty 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 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

Heap-based buffer overflow in Mozilla's nsBlockFrame::MarkLineDirty function allows remote attackers to execute arbitrary code via unspecified vectors. This memory corruption vulnerability in the layout/rendering engine affects Firefox, Thunderbird, and SeaMonkey versions prior to 15.0/10.0.7/2.12.

MitigationUpdate to Firefox 15.0+, Firefox ESR 10.0.7+, Thunderbird 15.0+, Thunderbird ESR 10.0.7+, or SeaMonkey 2.12+. Alternatively, disable or restrict JavaScript execution as an interim workaround.

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:< 15.0>= 10.0, < 10.0.7
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 Server EusOperating system
Affected:= 6.3
Enterprise Linux WorkstationOperating system
Affected:= 5.0= 6.0
Ubuntu LinuxOperating system
Affected:= 10.04= 11.04= 11.10= 12.04
SeamonkeyApplication
Affected:< 2.12

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 Firefox, Thunderbird, or SeaMonkey installation by looking for the executable: On Linux, run 'which firefox thunderbird seamonkey' or check /usr/bin/ for these binaries. On Windows, check Program Files folders.
    Affected if Any of Firefox, Thunderbird, or SeaMonkey is installed
  2. Determine Firefox version
    Run 'firefox --version' or 'firefox -v' from command line, or look in Firefox menu > Help > About.
    Affected if Version is less than 15.0, or version is 10.0.x where x is less than 7
  3. Determine SeaMonkey version
    Run 'seamonkey --version' or look in SeaMonkey menu > Help > About.
    Affected if Version is less than 2.12
  4. Determine Thunderbird version
    Run 'thunderbird --version' or look in Thunderbird menu > Help > About.
    Affected if Version is less than 15.0, or version is 10.0.x where x is less than 7 (Thunderbird shares the same vulnerable rendering engine)
  5. Check Red Hat system packages
    On RHEL systems, query the installed package version using 'rpm -qa | grep -i firefox' or 'rpm -qa | grep -i thunderbird'.
    Affected if Package version matches Red Hat versions 5.0, 6.0, 6.3 for Desktop, Server, Workstation, or Eus variants
  6. Check Ubuntu system packages
    On Ubuntu systems, query installed version using 'dpkg -l | grep -i firefox' or 'dpkg -l | grep -i thunderbird' or 'dpkg -l | grep -i seamonkey'.
    Affected if Package version corresponds to Ubuntu 10.04, 11.04, 11.10, or 12.04

Your environment is affected if Firefox is below 15.0 (or 10.0.x below 10.0.7), SeaMonkey is below 2.12, or the installed Mozilla product package version matches the listed Red Hat or Ubuntu vulnerable releases.

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 2.12 / 10.0.7 / 15.0 or later
Fixed in 2.1210.0.715.0
Interim mitigation

Update to Firefox 15.0+, Firefox ESR 10.0.7+, Thunderbird 15.0+, Thunderbird ESR 10.0.7+, or SeaMonkey 2.12+. Alternatively, disable or restrict JavaScript execution as an interim workaround.

Recommended fix High confidence

Firefox 15.0 (or Firefox ESR 10.0.7), SeaMonkey 2.12, Thunderbird 15.0 (or Thunderbird ESR 10.0.7)

  1. Identify the installed Mozilla product (Firefox, Thunderbird, or SeaMonkey) using the system's package manager
  2. For Red Hat Enterprise Linux systems: Run 'yum update firefox' or 'yum update seamonkey' to apply the latest security patches
  3. For Ubuntu/Debian systems: Run 'apt-get update && apt-get upgrade firefox' or 'apt-get upgrade seamonkey'
  4. Verify the installed version matches the fixed release (Firefox >= 15.0, Firefox ESR >= 10.0.7, SeaMonkey >= 2.12)
  5. Restart the browser/application after the update completes
Caveat Some legacy extensions or plugins may not be compatible with the newer major version; test in non-production environment first if using in an enterprise setting

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

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
18.0 hours of engineering $3,080
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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-2012-3957 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