Update CONTRIBUTING.md

Author: hyandell

CONTRIBUTING.md

@@ -50,6 +50,10 @@ For more information see the [Code of Conduct FAQ](https://aws.github.io/code-of
 opensource-codeofconduct@amazon.com with any additional questions or comments.
 
 
+## Security issue notifications
+If you discover a potential security issue in this project we ask that you notify AWS/Amazon Security via our [vulnerability reporting page](http://aws.amazon.com/security/vulnerability-reporting/). Please do **not** create a public github issue.
+
+
 ## Licensing
 
 See the [LICENSE](https://github.com/amzn/oss-dashboard/blob/master/LICENSE) file for our project's licensing. We will ask you confirm the licensing of your contribution.