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.net FrameworkApplication · Microsoft

CVE-2013-3133

HIGH · 9.3 CVSS v2.0 Published 2013-07-10
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
Microsoft .NET Framework 2.0 SP2, 3.5, 3.5.1, 4, and 4.5 does not properly check the permissions of objects that use reflection, which allows remote attackers to execute arbitrary code via (1) a crafted XAML browser application (XBAP) or (2) a crafted .NET Framework application, aka "Anonymous Method Injection Vulnerability."

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

This is a reflection permission bypass vulnerability in Microsoft .NET Framework versions 2.0 SP2 through 4.5. The framework fails to properly validate permissions when objects use reflection, allowing attackers to bypass Code Access Security (CAS) restrictions. Remote attackers can achieve arbitrary code execution by tricking users into visiting malicious websites hosting crafted XAML browser applications (XBAP) or running malicious .NET applications.

MitigationApply Microsoft security updates for .NET Framework. For browser-based attacks, disable XAML browser applications (XBAP) in Internet Explorer or use elevated trust configurations. For enterprise deployments, test .NET patches thoroughly as they may affect dependent applications.

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
.net FrameworkApplication
Affected:= 2.0= 3.5= 3.5.1= 4.0= 4.5

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 .NET Framework version
    Open Registry Editor and navigate to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full (for .NET 4.x) or HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v2.0 (for .NET 2.0/3.x). Check the Version value in the Install subkey. Alternatively, run 'dir %WINDIR%\Microsoft.NET\Framework' from command prompt to list installed directories.
    Affected if Version matches 2.0 SP2 or later, 3.5, 3.5.1, 4.0, or 4.5 (check specific version numbers against Microsoft documentation for the exact affected range)
  2. Verify XBAP execution is permitted in Internet Explorer
    In Internet Explorer, go to Internet Options > Security > Custom Level. Look for the setting labeled 'Enable XAML browser applications' or 'Run components signed with Authenticode'.
    Affected if XBAP execution is set to Enable or Prompt (not Disabled)
  3. Confirm .NET applications can execute
    Check that .NET Framework is not fully disabled via Group Policy or enterprise configuration. Run 'reg query "HKLM\SOFTWARE\Microsoft\.NETFramework" /v Policy' to check if CLR is disabled.
    Affected if CLR is enabled and .NET applications can run without restriction

Your environment is affected if you have any affected .NET Framework version (2.0 SP2 through 4.5) installed AND either XBAP is enabled in Internet Explorer or users can run untrusted .NET applications.

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

Apply Microsoft security updates for .NET Framework. For browser-based attacks, disable XAML browser applications (XBAP) in Internet Explorer or use elevated trust configurations. For enterprise deployments, test .NET patches thoroughly as they may affect dependent applications.

Recommended fix High confidence

Migrate to a supported .NET version (e.g., .NET Framework 4.8 LTS or .NET 6/7/8)

  1. Apply Microsoft Security Update MS13-052 which addresses CVE-2013-3133
  2. For .NET Framework 2.0 SP2: Install security update KB2808752
  3. For .NET Framework 3.5 and 3.5.1: Install security update KB2808752
  4. For .NET Framework 4.0: Install security update KB2804576
  5. For .NET Framework 4.5: Install security update KB2804576
  6. After applying updates, restart affected systems
  7. Verify updates are installed by checking Windows Update history or using the Microsoft Update Catalog
Caveat Legacy .NET Framework applications may require code modifications when migrating to newer .NET versions; comprehensive testing is required

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

Fix this in .net Framework Scoped from the published advisory
  • Consultation6.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,160
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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-2013-3133 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