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FirefoxWeb browser · Mozilla

CVE-2012-1974

HIGH · 10.0 CVSS v2.0 Published 2012-08-29
Fix available
A fix is available. Upgrade to 10.0.7 / 15.0 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::CanBreakLineBefore 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 Firefox, Thunderbird, SeaMonkey, and ESR versions in the gfxTextRun::CanBreakLineBefore function allows remote attackers to execute arbitrary code or cause heap memory corruption via unspecified vectors.

MitigationUpgrade affected Mozilla products to Firefox 15.0+, Firefox ESR 10.0.7+, Thunderbird 15.0+, Thunderbird ESR 10.0.7+, or SeaMonkey 2.12+ to resolve the vulnerability.

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
Debian LinuxOperating system
Affected:= 6.0= 7.0

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
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 Firefox version
    Run 'firefox --version' or check Help > About Firefox in the application menu
    Affected if Version is before 15.0, or between 10.0 and 10.0.6 inclusive
  2. Identify installed Thunderbird version
    Run 'thunderbird --version' or check Help > About Thunderbird
    Affected if Version is before 15.0, or between 10.0 and 10.0.6 inclusive
  3. Identify installed SeaMonkey version
    Run 'seamonkey --version' or check Help > About SeaMonkey
    Affected if Version is before 2.12 (equivalent to the fixed Firefox 15.0 release)
  4. Check for Firefox ESR installation
    Run 'firefox --version' and look for 'ESR' in the version string, or check the installed package details via package manager
    Affected if ESR version is between 10.0 and 10.0.6 inclusive
  5. Verify text rendering is in use
    The vulnerability is in the gfxTextRun::CanBreakLineBefore function within the graphics rendering subsystem; any use of Firefox, Thunderbird, or SeaMonkey that displays web content or email with text triggers the affected code path
    Affected if The application is actively rendering text content in web pages or email messages

You are affected if you are running any version of Firefox, Thunderbird, or SeaMonkey that is less than 15.0 (or less than 2.12 for SeaMonkey) or any ESR version between 10.0 and 10.0.6.

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 10.0.7 / 15.0 or later
Fixed in 10.0.715.0
Interim mitigation

Upgrade affected Mozilla products to Firefox 15.0+, Firefox ESR 10.0.7+, Thunderbird 15.0+, Thunderbird ESR 10.0.7+, or SeaMonkey 2.12+ to resolve the vulnerability.

Recommended fix High confidence

Firefox 15.0 or later, or Firefox ESR 10.0.7 or later

  1. 1. Open Firefox and navigate to Help > About Firefox (or go to about:support)
  2. 2. Check the current Firefox version under 'Application Basics'
  3. 3. If version is below 15.0 (or below 10.0.7 for ESR), click 'Check for Updates' or visit https://www.mozilla.org/firefox/ to download the latest version
  4. 4. Download Firefox 15.0 or later (or Firefox ESR 10.0.7 for enterprise environments)
  5. 5. Close all Firefox windows
  6. 6. Run the installer and follow the prompts to upgrade
  7. 7. After installation, restart Firefox and verify the version in Help > About Firefox shows 15.0+ (or 10.0.7+ for ESR)

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

Fix this in Firefox Scoped from the published advisory
  • Consultation1.0 h
  • Implementation2.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,040
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,664.

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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-2012-1974 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