This security update resolves a vulnerability in Microsoft Windows. The vulnerability could allow denial of service if an attacker sends a specially crafted HTTP packet to a target system.
This security update is rated Important for all supported editions of Microsoft Windows 10. For more information, see the Affected Software section.
The update addresses the vulnerability by modifying how the Windows HTTP protocol stack handles HTTP 2.0 requests. For more information about the vulnerability, see the Vulnerability Information section.
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 April bulletin summary.
 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](http://catalog.update.microsoft.com/v7/site/home.aspx) Windows.
\*The Updates Replaced column shows only the latest update in any chain of superseded updates. For a comprehensive list of updates replaced, go to the [Microsoft Update Catalog](http://catalog.update.microsoft.com/v7/site/home.aspx), search for the update KB number, and then view update details (updates replaced information is provided on the Package Details tab).
**Note** Windows Server 2016 Technical Preview 4 and Windows Server 2016 Technical Preview 5 are affected. Customers running these operating systems are encouraged to apply the update, which is available via [Windows Update](http://go.microsoft.com/fwlink/?linkid=21130).
HTTP.sys Denial of Service Vulnerability - CVE-2016-0150
A denial of service vulnerability exists in the HTTP 2.0 protocol stack (HTTP.sys) when HTTP.sys improperly parses specially crafted HTTP 2.0 requests. An attacker who successfully exploited the vulnerability could create a denial of service condition, causing the target system to become unresponsive.
To exploit this vulnerability, an attacker could send a specially crafted HTTP packet to a target system, causing the affected system to become nonresponsive. The update addresses the vulnerability by modifying how the Windows HTTP protocol stack handles HTTP 2.0 requests. Note that the denial of service vulnerability would not allow an attacker to execute code or to elevate user rights.
The following table contains a link to the standard entry for each vulnerability in the Common Vulnerabilities and Exposures list:
### Mitigating Factors
Microsoft has not identified any [mitigating factors](https://technet.microsoft.com/library/security/dn848375.aspx) for this vulnerability.
The Microsoft has not identified any [workarounds](https://technet.microsoft.com/library/security/dn848375.aspx) for this vulnerability.
Security Update Deployment
For Security Update Deployment information, see the Microsoft Knowledge Base article referenced [here](#kbarticle) in the Executive Summary.
Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See [Acknowledgments](https://technet.microsoft.com/library/security/dn820091.aspx) for more information.
The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
- V1.0 (April 12, 2016): Bulletin published.
*Page generated 2016-04-05 10:14-07:00.*