http://www.beyondweblogs.com/post/SharePoint-security-access-denied-permission-corruption-problem-Edit-Item-and-Access-Workflows.aspx
http://blogs.technet.com/srd/archive/2010/04/29/sharepoint-xss-issue.aspx
Here the workarounds
http://www.microsoft.com/technet/security/advisory/983438.mspx
http://www.hezser.de/blog/Lists/Beitraege/Post.aspx?ID=128
http://www.sharepointblogs.com/dwise/archive/2007/11/05/RenderFailedTotalsGroup.aspx