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FirefoxWeb browser · Mozilla

CVE-2011-3655

HIGH · 9.3 CVSS v2.0 Published 2011-11-09
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
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
Mozilla Firefox 4.x through 7.0 and Thunderbird 5.0 through 7.0 perform access control without checking for use of the NoWaiverWrapper wrapper, which allows remote attackers to gain privileges via a crafted web site.

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

Mozilla Firefox 4.x-7.0 and Thunderbird 5.0-7.0 contain an access control bypass vulnerability where the NoWaiverWrapper is not properly checked, allowing a malicious website to bypass same-origin policy restrictions and escalate privileges.

MitigationUpgrade to Firefox 8.0 and Thunderbird 8.0 or later, which contain the patched versions of the affected software.

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:= 4.0= 4.0.1= 5.0= 5.0.1= 6.0= 6.0.1= 6.0.2= 7.0
ThunderbirdApplication
Affected:= 5.0= 6.0= 6.0.1= 6.0.2= 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
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 Firefox version
    In Firefox, go to Help > About Firefox, or type 'about:support' in the address bar and look for the version number
    Affected if The version listed is 4.0, 4.0.1, 5.0, 5.0.1, 6.0, 6.0.1, 6.0.2, or 7.0
  2. Identify installed Mozilla Thunderbird version
    In Thunderbird, go to Help > About Thunderbird, or check the application log or package manager for the installed version
    Affected if The version listed is 5.0, 6.0, 6.0.1, 6.0.2, or 7.0
  3. Confirm only Firefox is in use
    If both Firefox and Thunderbird are installed, check both separately; if only one product is present, verify that product's version against the affected list
    Affected if Either product has a version within the affected ranges and is actively used

You are affected if you are running any version of Firefox 4.0 through 7.0 or Thunderbird 5.0 through 7.0 on your system.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade to Firefox 8.0 and Thunderbird 8.0 or later, which contain the patched versions of the affected software.

Recommended fix High confidence

Firefox 8.0 or later / Thunderbird 8.0 or later

  1. Back up bookmarks, passwords, and important data from the current Firefox/Thunderbird installation
  2. Download Firefox 8.0 or later from the official Mozilla website (www.mozilla.org)
  3. Download Thunderbird 8.0 or later from the official Mozilla website (www.mozilla.org)
  4. Install the new version, selecting the option to import settings from the previous installation
  5. Restart the application and verify the version number in Help > About Firefox/Thunderbird
  6. Ensure NoWaiverWrapper functionality is working correctly in the new version
Caveat Minor - Some older extensions may be incompatible with the newer major version; review extension compatibility before upgrading

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

Fix this in Firefox Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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Scan for this in your stack

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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-2011-3655 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