Microsoft Security Bulletin MS16-091 - Important
Security Update for .NET Framework (3170048)
Published: July 12, 2016 | Updated: November 8, 2016
Version: 1.1
Executive Summary
This security update resolves a vulnerability in Microsoft .NET Framework. The vulnerability could cause information disclosure if an attacker uploads a specially crafted XML file to a web-based application.
This security update is rated Important for Microsoft .NET Framework 2.0 Service Pack 2, Microsoft .NET Framework 3.5, Microsoft .NET Framework 3.5.1, Microsoft .NET Framework 4.5.2, Microsoft .NET Framework 4.6, and Microsoft .NET Framework 4.6.1 on affected releases of Microsoft Windows. For more information, see the Affected Software and Vulnerability Severity Ratings section.
The update addresses the vulnerability by modifying the way that the XML External Entity (XXE) parser parses XML input. For more information about the vulnerability, see the Vulnerability Information section.
For more information about this update, see Microsoft Knowledge Base Article 3170048.
Affected Software and Vulnerability Severity Ratings
The following software versions or editions are affected. Versions or editions that are not listed are either past their support life cycle or are not affected. To determine the support life cycle for your software version or edition, see Microsoft Support Lifecycle.
The severity ratings indicated for each affected software assume the potential maximum impact of the vulnerability. For information regarding the likelihood, within 30 days of this security bulletin’s release, of the exploitability of the vulnerability in relation to its severity rating and security impact, please see the Exploitability Index in the July bulletin summary.
**Operating System** | **Component ** | [**.NET Information Disclosure Vulnerability - CVE-2016-3255**](http://www.cve.mitre.org/cgi-bin/cvename.cgi?name=cve-2016-3255) | **Updates Replaced ** |
**Windows Vista** | |||
Windows Vista Service Pack 2 | [Microsoft .NET Framework 2.0 Service Pack 2](https://www.microsoft.com/downloads/details.aspx?familyid=003ced35-ba88-4b3a-94e5-8304976c5b69) (3163244) | **Important** Information Disclosure | None |
Windows Vista Service Pack 2 | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=177562b4-bc80-4199-bf03-27f243db0a4d)[1] (3163251) | **Important** Information Disclosure | None |
Windows Vista Service Pack 2 | [Microsoft .NET Framework 4.6](https://www.microsoft.com/downloads/details.aspx?familyid=ea7703a3-cd1b-4ff4-a156-117fa3aafd89)[1] (3164025) | **Important** Information Disclosure | None |
Windows Vista x64 Edition Service Pack 2 | [Microsoft .NET Framework 2.0 Service Pack 2](https://www.microsoft.com/downloads/details.aspx?familyid=003ced35-ba88-4b3a-94e5-8304976c5b69) (3163244) | **Important** Information Disclosure | None |
Windows Vista x64 Edition Service Pack 2 | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=177562b4-bc80-4199-bf03-27f243db0a4d) [1] (3163251) | **Important** Information Disclosure | None |
Windows Vista x64 Edition Service Pack 2 | [Microsoft .NET Framework 4.6](https://www.microsoft.com/downloads/details.aspx?familyid=ea7703a3-cd1b-4ff4-a156-117fa3aafd89)[1] (3164025) | **Important** Information Disclosure | None |
**Windows Server 2008** | |||
Windows Server 2008 for 32-bit Systems Service Pack 2 | [Microsoft .NET Framework 2.0 Service Pack 2](https://www.microsoft.com/downloads/details.aspx?familyid=003ced35-ba88-4b3a-94e5-8304976c5b69) (3163244) | **Important** Information Disclosure | None |
Windows Server 2008 for 32-bit Systems Service Pack 2 | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=177562b4-bc80-4199-bf03-27f243db0a4d) [1] (3163251) | **Important** Information Disclosure | None |
Windows Server 2008 for 32-bit Systems Service Pack 2 | [Microsoft .NET Framework 4.6](https://www.microsoft.com/downloads/details.aspx?familyid=ea7703a3-cd1b-4ff4-a156-117fa3aafd89)[1] (3164025) | **Important** Information Disclosure | None |
Windows Server 2008 for x64-based Systems Service Pack 2 | [Microsoft .NET Framework 2.0 Service Pack 2](https://www.microsoft.com/downloads/details.aspx?familyid=003ced35-ba88-4b3a-94e5-8304976c5b69) (3163244) | **Important** Information Disclosure | None |
Windows Server 2008 for x64-based Systems Service Pack 2 | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=177562b4-bc80-4199-bf03-27f243db0a4d) [1] (3163251) | **Important** Information Disclosure | None |
Windows Server 2008 for x64-based Systems Service Pack 2 | [Microsoft .NET Framework 4.6](https://www.microsoft.com/downloads/details.aspx?familyid=ea7703a3-cd1b-4ff4-a156-117fa3aafd89)[1] (3164025) | **Important** Information Disclosure | None |
Windows Server 2008 for Itanium-based Systems Service Pack 2 | [Microsoft .NET Framework 2.0 Service Pack 2](https://www.microsoft.com/downloads/details.aspx?familyid=003ced35-ba88-4b3a-94e5-8304976c5b69) (3163244) | **Important** Information Disclosure | None |
**Windows 7** | |||
Windows 7 for 32-bit Systems Service Pack 1 | [Microsoft .NET Framework 3.5.1](https://www.microsoft.com/downloads/details.aspx?familyid=e4bc950e-28a4-45ab-a733-bf9894f6a7ea) (3163245) | **Important** Information Disclosure | None |
Windows 7 for 32-bit Systems Service Pack 1 | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=177562b4-bc80-4199-bf03-27f243db0a4d)[1] (3163251) | **Important** Information Disclosure | None |
Windows 7 for 32-bit Systems Service Pack 1 | [Microsoft .NET Framework 4.6/4.6.1](https://www.microsoft.com/downloads/details.aspx?familyid=ea7703a3-cd1b-4ff4-a156-117fa3aafd89)[1] (3164025) | **Important** Information Disclosure | None |
Windows 7 for x64-based Systems Service Pack 1 | [Microsoft .NET Framework 3.5.1](https://www.microsoft.com/downloads/details.aspx?familyid=e4bc950e-28a4-45ab-a733-bf9894f6a7ea) (3163245) | **Important** Information Disclosure | None |
Windows 7 for x64-based Systems Service Pack 1 | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=177562b4-bc80-4199-bf03-27f243db0a4d)[1] (3163251) | **Important** Information Disclosure | None |
Windows 7 for x64-based Systems Service Pack 1 | [Microsoft .NET Framework 4.6/4.6.1](https://www.microsoft.com/downloads/details.aspx?familyid=ea7703a3-cd1b-4ff4-a156-117fa3aafd89)[1] (3164025) | **Important** Information Disclosure | None |
**Windows Server 2008 R2** | |||
Windows Server 2008 R2 for x64-based Systems Service Pack 1 | [Microsoft .NET Framework 3.5.1](https://www.microsoft.com/downloads/details.aspx?familyid=e4bc950e-28a4-45ab-a733-bf9894f6a7ea) (3163245) | **Important** Information Disclosure | None |
Windows Server 2008 R2 for x64-based Systems Service Pack 1 | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=177562b4-bc80-4199-bf03-27f243db0a4d)[1] (3163251) | **Important** Information Disclosure | None |
Windows Server 2008 R2 for x64-based Systems Service Pack 1 | [Microsoft .NET Framework 4.6/4.6.1](https://www.microsoft.com/downloads/details.aspx?familyid=ea7703a3-cd1b-4ff4-a156-117fa3aafd89)[1] (3164025) | **Important** Information Disclosure | None |
Windows Server 2008 R2 for Itanium-based Systems Service Pack 1 | [Microsoft .NET Framework 3.5.1](https://www.microsoft.com/downloads/details.aspx?familyid=e4bc950e-28a4-45ab-a733-bf9894f6a7ea) (3163245) | **Important** Information Disclosure | None |
**Windows 8.1** | |||
Windows 8.1 for 32-bit Systems | [Microsoft .NET Framework 3.5](https://www.microsoft.com/downloads/details.aspx?familyid=88523492-3af6-426f-8693-931b372bd725) (3163247) | **Important** Information Disclosure | None |
Windows 8.1 for 32-bit Systems | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=00373d7a-d3d3-4db0-bb99-d72ea71ae882)[1] (3163291) | **Important** Information Disclosure | None |
Windows 8.1 for 32-bit Systems | [Microsoft .NET Framework 4.6/4.6.1](https://www.microsoft.com/downloads/details.aspx?familyid=9bf68050-0761-4dbd-b425-69ec33c7a15b)[1] (3164024) | **Important** Information Disclosure | None |
Windows 8.1 for x64-based Systems | [Microsoft .NET Framework 3.5](https://www.microsoft.com/downloads/details.aspx?familyid=88523492-3af6-426f-8693-931b372bd725) (3163247) | **Important** Information Disclosure | None |
Windows 8.1 for x64-based Systems | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=00373d7a-d3d3-4db0-bb99-d72ea71ae882)[1] (3163291) | **Important** Information Disclosure | None |
Windows 8.1 for x64-based Systems | [Microsoft .NET Framework 4.6/4.6.1](https://www.microsoft.com/downloads/details.aspx?familyid=9bf68050-0761-4dbd-b425-69ec33c7a15b)[1] (3164024) | **Important** Information Disclosure | None |
**Windows Server 2012 and Windows Server 2012 R2** | |||
Windows Server 2012 | [Microsoft .NET Framework 3.5](https://www.microsoft.com/downloads/details.aspx?familyid=d9f1cc61-fd9a-467e-8f6e-6f8dc71337cf) (3163246) | **Important** Information Disclosure | None |
Windows Server 2012 | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=4020a8f4-be3d-47d4-93c7-24cd6cefd5a1)[1] (3163250) | **Important** Information Disclosure | None |
Windows Server 2012 | [Microsoft .NET Framework 4.6/4.6.1](https://www.microsoft.com/downloads/details.aspx?familyid=9016c4c7-e692-44f1-9b8d-524357e67e3d)[1] (3164023) | **Important** Information Disclosure | None |
Windows Server 2012 R2 | [Microsoft .NET Framework 3.5](https://www.microsoft.com/downloads/details.aspx?familyid=88523492-3af6-426f-8693-931b372bd725) (3163247) | **Important** Information Disclosure | None |
Windows Server 2012 R2 | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=00373d7a-d3d3-4db0-bb99-d72ea71ae882)[1] (3163291) | **Important** Information Disclosure | None |
Windows Server 2012 R2 | [Microsoft .NET Framework 4.6/4.6.1](https://www.microsoft.com/downloads/details.aspx?familyid=9bf68050-0761-4dbd-b425-69ec33c7a15b)[1] (3164024) | **Important** Information Disclosure | None |
**Windows RT 8.1** | |||
Windows RT 8.1 | Microsoft .NET Framework 4.5.2[1][2] (3163291) | **Important** Information Disclosure | None |
Windows RT 8.1 | Microsoft .NET Framework 4.6/4.6.1[1][2] (3164024) | **Important** Information Disclosure | None |
**Windows 10** | |||
[Windows 10 for 32-bit Systems](https://support.microsoft.com/kb/3163912)[3] (3163912) | Microsoft .NET Framework 3.5 | **Important** Information Disclosure | [3163017](https://support.microsoft.com/kb/3163017) |
[Windows 10 for 32-bit Systems](https://support.microsoft.com/kb/3163912)[3] (3163912) | Microsoft .NET Framework 4.6 | **Important** Information Disclosure | [3163017](https://support.microsoft.com/kb/3163017) |
[Windows 10 for x64-based Systems](https://support.microsoft.com/kb/3163912)[3] (3163912) | Microsoft .NET Framework 3.5 | **Important** Information Disclosure | [3163017](https://support.microsoft.com/kb/3163017) |
[Windows 10 for x64-based Systems](https://support.microsoft.com/kb/3163912)[3] (3163912) | Microsoft .NET Framework 4.6 | **Important** Information Disclosure | [3163017](https://support.microsoft.com/kb/3163017) |
[Windows 10 Version 1511 for 32-bit Systems](https://support.microsoft.com/kb/3172985)[3] (3172985) | Microsoft .NET Framework 3.5 | **Important** Information Disclosure | [3163018](https://support.microsoft.com/kb/3163018) |
[Windows 10 Version 1511 for 32-bit Systems](https://support.microsoft.com/kb/3172985)[3] (3172985) | Microsoft .NET Framework 4.6.1 | **Important** Information Disclosure | [3163018](https://support.microsoft.com/kb/3163018) |
[Windows 10 Version 1511 for x64-based Systems](https://support.microsoft.com/kb/3172985)[3] (3172985) | Microsoft .NET Framework 3.5 | **Important** Information Disclosure | [3163018](https://support.microsoft.com/kb/3163018) |
[Windows 10 Version 1511 for x64-based Systems](https://support.microsoft.com/kb/3172985)[3] (3172985) | Microsoft .NET Framework 4.6.1 | **Important** Information Disclosure | [3163018](https://support.microsoft.com/kb/3163018) |
**Server Core installation option** | |||
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) | [Microsoft .NET Framework 3.5.1](https://www.microsoft.com/downloads/details.aspx?familyid=e4bc950e-28a4-45ab-a733-bf9894f6a7ea) (3163245) | **Important** Information Disclosure | None |
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=177562b4-bc80-4199-bf03-27f243db0a4d)[1] (3163251) | **Important** Information Disclosure | None |
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation) | [Microsoft .NET Framework 4.6/4.6.1](https://www.microsoft.com/downloads/details.aspx?familyid=ea7703a3-cd1b-4ff4-a156-117fa3aafd89)[1] (3164025) | **Important** Information Disclosure | None |
Windows Server 2012 (Server Core installation) | [Microsoft .NET Framework 3.5](https://www.microsoft.com/downloads/details.aspx?familyid=d9f1cc61-fd9a-467e-8f6e-6f8dc71337cf) (3163246) | **Important** Information Disclosure | None |
Windows Server 2012 (Server Core installation) | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=4020a8f4-be3d-47d4-93c7-24cd6cefd5a1)[1] (3163250) | **Important** Information Disclosure | None |
Windows Server 2012 (Server Core installation) | [Microsoft .NET Framework 4.6/4.6.1](https://www.microsoft.com/downloads/details.aspx?familyid=9016c4c7-e692-44f1-9b8d-524357e67e3d)[1] (3164023) | **Important** Information Disclosure | None |
Windows Server 2012 R2 (Server Core installation) | [Microsoft .NET Framework 3.5](https://www.microsoft.com/downloads/details.aspx?familyid=88523492-3af6-426f-8693-931b372bd725) (3163247) | **Important** Information Disclosure | None |
Windows Server 2012 R2 (Server Core installation) | [Microsoft .NET Framework 4.5.2](https://www.microsoft.com/downloads/details.aspx?familyid=00373d7a-d3d3-4db0-bb99-d72ea71ae882)[1] (3163291) | **Important** Information Disclosure | None |
Windows Server 2012 R2 (Server Core installation) | [Microsoft .NET Framework 4.6/4.6.1](https://www.microsoft.com/downloads/details.aspx?familyid=9bf68050-0761-4dbd-b425-69ec33c7a15b)[1] (3164024) | **Important** Information Disclosure | None |
[2]Windows RT 8.1 updates are available only via Windows Update.
[3]Windows 10 updates are cumulative. The monthly security release includes all security fixes for vulnerabilities that affect Windows 10, in addition to non-security updates. The updates are available via the Microsoft Update Catalog.
Note The vulnerability discussed in this bulletin affects Windows Server 2016 Technical Preview 4 and Windows Server 2016 Technical Preview 5. An update is available for Windows Server 2016 Technical Preview 5 via Windows Update. However, no update is available for Windows Server 2016 Technical Preview 4. To be protected from the vulnerability, Microsoft recommends that customers running Windows Server 2016 Technical Preview 4 upgrade to Windows Server 2016 Technical Preview 5.
Vulnerability Information
.NET Information Disclosure Vulnerability - CVE-2016-3255
An information disclosure vulnerability exists when .NET Framework improperly parses XML input containing a reference to an external entity. An attacker who successfully exploited this vulnerability could read arbitrary files via an XML external entity declaration.
To exploit the vulnerability, an attacker could create specially crafted XML data and induce an application to parse and validate the XML data. For example, an attacker could create an XML file and upload it to a web-based application. The update addresses the vulnerability by modifying the way that the XML External Entity (XXE) parser parses XML input.
The following table contains links to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:
Vulnerability title | CVE number | Publicly disclosed | Exploited |
.NET Information Disclosure Vulnerability | CVE-2016-3255 | No | No |