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FirefoxWeb browser · Mozilla

CVE-2011-2995

HIGH · 10.0 CVSS v2.0 Published 2011-09-29
Fix available
A fix is available. Upgrade to after 6.0.2 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
Multiple unspecified vulnerabilities in the browser engine in Mozilla Firefox before 3.6.23 and 4.x through 6, Thunderbird before 7.0, and SeaMonkey before 2.4 allow remote attackers to cause a denial of service (memory corruption and application crash) or possibly execute arbitrary code via unknown 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

Multiple memory corruption vulnerabilities in Mozilla's browser engine allow remote attackers to crash Firefox, Thunderbird, or SeaMonkey and potentially execute arbitrary code through unknown attack vectors in the rendering engine.

MitigationUpdate affected Mozilla products (Firefox <3.6.23 or 4.x-6, Thunderbird <7.0, SeaMonkey <2.4) to patched versions to remediate the memory corruption vulnerabilities.

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:<= 3.6.22= 3.6= 3.6.2= 3.6.3= 3.6.4= 3.6.6= 3.6.7= 3.6.8= 3.6.9= 3.6.10= 3.6.11= 3.6.12
ThunderbirdApplication
Affected:<= 6.0.2= 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
SeamonkeyApplication
Affected:<= 2.3.3= 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= 1.0.99

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 if Firefox, Thunderbird, or SeaMonkey is installed by looking for the application in standard installation directories or using package manager commands (dpkg -l, rpm -qa, or similar)
    Affected if Any of these three Mozilla products are installed
  2. Determine Firefox version
    Run 'firefox --version' from command line, or check Help > About Firefox in the application menu
    Affected if Version is 3.6.x up to and including 3.6.22, or exactly 3.6, 3.6.2, 3.6.3, 3.6.4, 3.6.6, 3.6.7, 3.6.8, 3.6.9, 3.6.10, 3.6.11, or 3.6.12
  3. Determine Thunderbird version
    Run 'thunderbird --version' from command line, or check Help > About Thunderbird in the application menu
    Affected if Version is 6.0.2 or lower, or exactly 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.7.1, 0.7.2, 0.7.3, or 0.8
  4. Determine SeaMonkey version
    Run 'seamonkey --version' from command line, or check Help > About SeaMonkey in the application menu
    Affected if Version is 2.3.3 or lower, or exactly 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, or 1.0.99

The environment is affected if any Firefox version 3.6.x up to 3.6.22, any Thunderbird version up to 6.0.2, or any SeaMonkey version up to 2.3.3 is installed and actively used for browsing or email rendering.

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 6.0.2
Interim mitigation

Update affected Mozilla products (Firefox <3.6.23 or 4.x-6, Thunderbird <7.0, SeaMonkey <2.4) to patched versions to remediate the memory corruption vulnerabilities.

Recommended fix High confidence

Firefox 3.6.23 or 7+; Thunderbird 7.0+; SeaMonkey 2.4+

  1. 1. Identify which Mozilla product is affected (Firefox, Thunderbird, or SeaMonkey) and note the current installed version
  2. 2. Back up any important bookmarks, emails, or profile data before upgrading
  3. 3. For Firefox 3.6.x users: Upgrade to Firefox 3.6.23 or later (or migrate to Firefox 7+)
  4. 4. For Firefox 4.x-6.x users: Upgrade to Firefox 7 or later
  5. 5. For Thunderbird users: Upgrade to Thunderbird 7.0 or later
  6. 6. For SeaMonkey users: Upgrade to SeaMonkey 2.4 or later
  7. 7. Restart the application and verify it launches without errors
  8. 8. Confirm the version number matches the expected fixed release
Caveat Upgrading to newer major versions (e.g., Firefox 7+ from 3.6.x) may introduce UI changes and require profile migration; also ensure compatible extensions/themes

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
  • Testing6.0 h
  • Review / QA3.0 h
27.0 hours of engineering $4,800
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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-2011-2995 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