This patch is deprecated. Please use SUPEE-9767 v2 instead. This patch needs to be reverted prior to installed the new version.
This patch provides protection against several types of security-related issues, including remote code execution, information leaks and cross-site scripting. - Added May 30, 2017

NOTE: This patch has known issues. More information about the individual issues addressed by this patch as well as known issues is available in the patch details.

More details about the patch issues could be found here.