Magento today released a new cumulative security patch for Magento Enterprise and Community (SUPEE-5994). Here's Magento explanation of this security update:
To further secure the Magento platform from potential attacks, we are releasing a new patch (SUPEE-5994) with multiple critical security fixes today. The patch addresses a range of issues, including scenarios where attackers can gain access to customer information. These vulnerabilities were gathered through our multi-point security program, and we have received no reports of merchants or their customers being impacted by these issues.
All versions of Magento Enterprise Edition and Magento Community Edition software are impacted and we strongly recommend that you immediately deploy the patch and encourage your customers to do the same. Please note that this patch should be installed in addition to the recent Shoplift patch (SUPEE-5344). More information about the security issues is available in the Appendix of the Magento Enterprise Edition and Magento Community Edition user guides.
Modern Retail has updated your Magento website with this latest patch. If you have any questions about this patch please submit a Support Request and we'd be happy to help you out. Thank you.
Important New Magento Security Patch Announcement