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FirefoxWeb browser · Mozilla

CVE-2011-2363

HIGH · 10.0 CVSS v2.0 Published 2011-06-30
Fix available
A fix is available. Upgrade to after 3.6.17 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 nsSVGPointList::AppendElement function in the implementation of SVG element lists in Mozilla Firefox before 3.6.18, Thunderbird before 3.1.11, and SeaMonkey through 2.0.14 allows remote attackers to cause a denial of service (application crash) or possibly execute arbitrary code via vectors involving a user-supplied callback.

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's SVG implementation where nsSVGPointList::AppendElement improperly handles memory after a user-supplied callback is processed, allowing remote attackers to potentially execute arbitrary code via crafted SVG content.

MitigationApply vendor-supplied updates: Firefox 3.6.18+, Thunderbird 3.1.11+, or SeaMonkey 2.0.14+. If immediate patching is not feasible, disable SVG rendering or restrict JavaScript execution in untrusted contexts.

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:<= 3.6.17= 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= 1.5= 1.5.0.1
SeamonkeyApplication
Affected:= 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= 1.1.1
ThunderbirdApplication
Affected:<= 3.1.10= 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
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, SeaMonkey, or Thunderbird by looking for their executables or checking the application directory. On Windows, check Program Files; on Linux, check /usr/lib or /opt; on macOS, check /Applications.
    Affected if Any of these three products is installed
  2. Determine product version
    Run the application with --version flag, or check the About dialog within the application, or inspect the application manifest or version file in the installation directory.
    Affected if Version matches affected ranges: Firefox <= 3.6.17, Firefox 1.0.x, Firefox 1.5.x; SeaMonkey 1.0.x through 1.1.1; Thunderbird <= 3.1.10, Thunderbird 0.x versions
  3. Check if SVG rendering is enabled
    In Firefox/SeaMonkey, go to about:config and check if svg.enabled is true, or verify that the browser renders SVG content by visiting a test SVG page. In Thunderbird, check if SVG images are displayed in emails.
    Affected if SVG rendering is enabled and the product version is in the affected list
  4. Confirm SVGPointList functionality is accessible
    Attempt to load or display a simple SVG document in the browser, or verify the SVG DOM is accessible via JavaScript by checking if document.createElementNS works with the SVG namespace.
    Affected if SVG content can be processed and the product version is vulnerable

User is affected if a vulnerable Mozilla product version (Firefox <= 3.6.17, Firefox 1.0.x/1.5.x, SeaMonkey 1.0.x/1.1.x, Thunderbird <= 3.1.10 or 0.x) is installed with SVG rendering enabled and capable of processing SVG content.

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 3.6.17
Interim mitigation

Apply vendor-supplied updates: Firefox 3.6.18+, Thunderbird 3.1.11+, or SeaMonkey 2.0.14+. If immediate patching is not feasible, disable SVG rendering or restrict JavaScript execution in untrusted contexts.

Recommended fix High confidence

Firefox 3.6.18+, Thunderbird 3.1.11+, SeaMonkey 2.0.15+; or migrate to currently supported versions

  1. Upgrade Firefox to version 3.6.18 or higher (or migrate to a supported modern Firefox release)
  2. Upgrade Thunderbird to version 3.1.11 or higher (or migrate to a supported modern Thunderbird release)
  3. Upgrade SeaMonkey to version 2.0.15 or higher (or migrate to a supported modern SeaMonkey release)
Caveat These are very old 2010-2011 era products. Firefox 3.6.x and Thunderbird 3.x are obsolete and no longer receive security updates. Users should migrate to modern supported versions for ongoing protection.

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
  • Testing1.0 h
  • Review / QA1.0 h
5.0 hours of engineering $890
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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-2011-2363 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