ENISA (European Network and information Security Agency) has released an analysis report on the vulnerabilities that exist in the draft of HTML5. The full report is available at http://www.enisa.europa.eu/act/application-security/web-security/a-security-analysis-of-next-generation-web-standards/at_download/fullReport
You can read the press release at Web security: EU cyber-security Agency ENISA flags security fixes for new web standards/HTML5
If you just want the summary of the report, then look at pages 2 and 3.
Dr.Giles Hogben has been very impressive over the years with his research on Social Media, Cloud Computing and now Web Standards.