dbcve.org
.net FrameworkApplication · Microsoft

CVE-2016-7270

HIGH · 7.5 CVSS v3.0 Published 2016-12-20
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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 Data Provider for SQL Server in Microsoft .NET Framework 4.6.2 mishandles a developer-supplied key, which allows remote attackers to bypass the Always Encrypted protection mechanism and obtain sensitive cleartext information by leveraging key guessability, aka ".NET Information Disclosure 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

A vulnerability in the .NET Framework 4.6.2 SQL Server Data Provider allows attackers to bypass the Always Encrypted feature by exploiting improper handling of developer-supplied encryption keys. The weakness stems from key guessability, enabling remote attackers to obtain sensitive data in cleartext by cracking the encryption key rather than breaking the encryption algorithm itself.

MitigationApply Microsoft security updates for .NET Framework 4.6.2 and ensure encryption keys used with Always Encrypted meet current cryptographic strength standards. Consider key rotation and review key management practices.

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:= 4.6.2

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
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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. Confirm .NET Framework 4.6.2 is installed
    Check the installed .NET Framework version by inspecting the registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Client or Full, looking for Release value 394802 (which corresponds to 4.6.2), or use the command 'reg query "HKLM\SOFTWARE\Microsoft\NET Framework Setup\NDP\v4" /s' to list all installed versions.
    Affected if The installed .NET Framework version is exactly 4.6.2 (release 394802).
  2. Determine if Always Encrypted is in use
    Review application source code for use of SqlConnectionStringBuilder with "Column Encryption Setting=Enabled" in connection strings, or search for references to SqlColumnEncryptionCertificateStoreProvider, SqlColumnEncryptionCngProvider, or related Always Encrypted APIs in the codebase.
    Affected if The application uses Always Encrypted with the .NET Framework SQL Server Data Provider (System.Data.SqlClient).
  3. Identify if developer-supplied encryption keys are used
    Search the codebase and configuration files for custom implementations of column master key (CMK) providers, specifically implementations of SqlColumnEncryptionKeyStoreProvider interface that use developer-provided keys rather than Windows Certificate Store or CNG providers managed by SQL Server.
    Affected if Custom SqlColumnEncryptionKeyStoreProvider implementations are present that use hardcoded, configurable, or otherwise developer-supplied encryption keys instead of properly managed keys.
  4. Review encryption key configuration
    Inspect any configuration files (app.config, web.config) or custom key management code for entries under <columnEncryptionKeyStoreProviders> that define custom key providers, and examine how the column master key is stored and retrieved.
    Affected if Custom key store providers are registered or keys are supplied through developer-managed configuration rather than through Azure Key Vault or Windows Certificate Store.

A user is affected if they have .NET Framework 4.6.2 installed AND use Always Encrypted with developer-supplied or custom-managed encryption keys that may be guessable.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Microsoft security updates for .NET Framework 4.6.2 and ensure encryption keys used with Always Encrypted meet current cryptographic strength standards. Consider key rotation and review key management practices.

Fix this in .net Framework Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA4.0 h
40.0 hours of engineering $7,000
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $11,200.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2016-7270 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2016-7270 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