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FirefoxWeb browser · Mozilla

CVE-2010-2766

HIGH · 9.3 CVSS v2.0 Published 2010-09-09
Fix available
A fix is available. Upgrade to after 3.5.11 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
The normalizeDocument function in Mozilla Firefox before 3.5.12 and 3.6.x before 3.6.9, Thunderbird before 3.0.7 and 3.1.x before 3.1.3, and SeaMonkey before 2.0.7 does not properly handle the removal of DOM nodes during normalization, which might allow remote attackers to execute arbitrary code via vectors involving access to a deleted object.

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 the normalizeDocument function where improper handling of DOM node removal during normalization leads to access of deleted objects, potentially allowing remote attackers to execute arbitrary code via crafted HTML content.

MitigationUpdate affected Mozilla products to patched versions: Firefox 3.5.12+/3.6.9+, Thunderbird 3.0.7+/3.1.3+, or SeaMonkey 2.0.7+. This is a critical arbitrary-code-execution vulnerability requiring immediate remediation.

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:= 3.6= 3.6.2= 3.6.3= 3.6.4= 3.6.6= 3.6.7= 3.6.8<= 3.5.11= 1.0= 1.0.1= 1.0.2= 1.0.3
SeamonkeyApplication
Affected:<= 2.0.6= 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= 1.0.9= 1.1
ThunderbirdApplication
Affected:<= 3.0.6= 0.1= 0.2= 0.3= 0.4= 0.5= 0.6= 0.7= 0.7.1= 0.7.2= 0.7.3= 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 which Mozilla application is installed: look for Firefox, Thunderbird, or SeaMonkey in the system (typically in Program Files on Windows, /Applications on macOS, or via package manager on Linux)
    Affected if Any of Firefox, Thunderbird, or SeaMonkey is installed on the system
  2. Determine Firefox version
    In Firefox, navigate to Help > About Firefox (or go to about:support) to display the full version number
    Affected if Version is 3.6, 3.6.2, 3.6.3, 3.6.4, 3.6.6, 3.6.7, 3.6.8, or any 3.5.x version through 3.5.11, or any 1.0.x version (1.0, 1.0.1, 1.0.2, 1.0.3)
  3. Determine SeaMonkey version
    In SeaMonkey, go to Help > About SeaMonkey to display the version number
    Affected if Version is 2.0.6 or lower, or any 1.0.x version (1.0 through 1.0.9), or version 1.1
  4. Determine Thunderbird version
    In Thunderbird, go to Help > About Thunderbird to display the version number
    Affected if Version is 3.0.6 or lower, or any 0.x version (0.1 through 0.8, including 0.7.1, 0.7.2, 0.7.3)

If any of these Mozilla products is installed and its version matches one listed in the affected ranges, the environment is vulnerable to arbitrary code execution via the normalizeDocument use-after-free flaw.

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 3.5.11
Interim mitigation

Update affected Mozilla products to patched versions: Firefox 3.5.12+/3.6.9+, Thunderbird 3.0.7+/3.1.3+, or SeaMonkey 2.0.7+. This is a critical arbitrary-code-execution vulnerability requiring immediate remediation.

Recommended fix High confidence

Firefox 3.6.9 or later (preferably 3.6.24); SeaMonkey 2.0.7 or later; Thunderbird 3.0.7 or 3.1.3 or later; or migrate to current stable releases of each product

  1. 1. Identify the currently installed Firefox, SeaMonkey, or Thunderbird version by navigating to Help > About [Product Name]
  2. 2. If Firefox 3.6.x is in use, upgrade to Firefox 3.6.24 (the final 3.6.x release) or preferably migrate to a supported Firefox ESR or current release
  3. 3. If SeaMonkey 1.x or 2.0.6 or earlier is in use, upgrade to SeaMonkey 2.0.7 or later, or migrate to a current supported version
  4. 4. If Thunderbird 3.0.x or earlier is in use, upgrade to Thunderbird 3.0.7 or later, or migrate to a current supported version
  5. 5. After upgrade, verify the version in Help > About to confirm the patch was applied
  6. 6. Ensure automatic updates are enabled or check for updates regularly to maintain security
Caveat Upgrading from Firefox 3.6.x may result in compatibility issues with legacy extensions or plugins that were designed for older versions; migrating to current releases provides better security but may require testing of existing workflows

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

Fix this in Firefox Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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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-2010-2766 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