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FirefoxWeb browser · Mozilla

CVE-2006-0749

HIGH · 9.3 CVSS v2.0 Published 2006-04-14
Fix available
A fix is available. Upgrade to 1.0 / 1.0.8 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
nsHTMLContentSink.cpp in Mozilla Firefox and Thunderbird 1.x before 1.5 and 1.0.x before 1.0.8, Mozilla Suite before 1.7.13, and SeaMonkey before 1.0 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via unknown vectors involving a "particular sequence of HTML tags" that leads to memory corruption.

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

Memory corruption vulnerability in nsHTMLContentSink.cpp in Mozilla Firefox, Thunderbird, Mozilla Suite, and SeaMonkey. A specific sequence of HTML tags triggers heap corruption during HTML parsing, potentially allowing remote code execution.

MitigationApply vendor patches: update Firefox to 1.5 or 1.0.8+, Thunderbird to 1.5 or 1.0.8+, Mozilla Suite to 1.7.13+, or SeaMonkey to 1.0+. If patching legacy products is infeasible, restrict HTML email rendering and web content from untrusted sources.

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:>= 1.0, < 1.5
Mozilla SuiteApplication
Affected:< 1.7.13
SeamonkeyApplication
Affected:< 1.0
ThunderbirdApplication
Affected:>= 1.0, < 1.0.8

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

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, Mozilla Suite, or SeaMonkey on the system. Look in standard installation directories such as Program Files, or check the application's executable properties (right-click the .exe and view VersionInfo).
    Affected if Any of these four Mozilla products is installed
  2. Determine Firefox version
    For Firefox: open the application and type 'about:firefox' in the address bar, or go to Help > About Firefox. Alternatively, right-click firefox.exe and select Properties > Details to view the File Version.
    Affected if The installed version is 1.0 or higher but lower than 1.5
  3. Determine Thunderbird version
    For Thunderbird: open the application and type 'about:thunderbird' in the address bar, or go to Help > About Thunderbird. Alternatively, right-click thunderbird.exe and select Properties > Details to view the File Version.
    Affected if The installed version is 1.0 or higher but lower than 1.0.8
  4. Determine Mozilla Suite version
    For Mozilla Suite: open the application and go to Help > About Mozilla Suite, or right-click the main executable (such as mozilla.exe) and select Properties > Details to view the File Version.
    Affected if The installed version is lower than 1.7.13
  5. Determine SeaMonkey version
    For SeaMonkey: open the application and go to Help > About SeaMonkey, or right-click the main executable and select Properties > Details to view the File Version.
    Affected if The installed version is lower than 1.0

If any of these four Mozilla products is installed and its version falls within the affected range (Firefox 1.0 to <1.5, Thunderbird 1.0 to <1.0.8, Mozilla Suite <1.7.13, or SeaMonkey <1.0), the environment is vulnerable to the HTML parsing heap corruption described in CVE-2006-0749.

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 1.0 / 1.0.8 / 1.5 or later
Fixed in 1.01.0.81.5
Interim mitigation

Apply vendor patches: update Firefox to 1.5 or 1.0.8+, Thunderbird to 1.5 or 1.0.8+, Mozilla Suite to 1.7.13+, or SeaMonkey to 1.0+. If patching legacy products is infeasible, restrict HTML email rendering and web content from untrusted sources.

Recommended fix High confidence

Latest stable Firefox/Thunderbird/SeaMonkey (currently Firefox 130+, Thunderbird 130+, SeaMonkey 2.53.x)

  1. 1. Identify the affected application (Firefox, Thunderbird, Mozilla Suite, or SeaMonkey) currently in use
  2. 2. Since Firefox 1.x, Thunderbird 1.x, Mozilla Suite, and SeaMonkey <1.0 are obsolete and no longer maintained, upgrade to a modern supported version
  3. 3. For Firefox users: Download and install the latest Firefox from https://www.mozilla.org/firefox/
  4. 4. For Thunderbird users: Download and install the latest Thunderbird from https://www.mozilla.org/thunderbird/
  5. 5. For SeaMonkey users: Download and install the latest SeaMonkey from https://www.seamonkey-project.org/
  6. 6. After upgrading, verify the new version is running (help > about)
Caveat Very low risk - these are major version jumps from 2005-era software to modern versions; all old extensions and add-ons will be incompatible and must be replaced

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

Fix this in Firefox Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA4.0 h
32.0 hours of engineering $5,580
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Scan for this in your stack

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dbcve dependency scanner

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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-2006-0749 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