Adobe has released update CS4 11.0.1 to address CVE-2010-1279 in Photoshop CS4 11.0.0. A vulnerability exist in which a malformed .TIFF that is opened in Photoshop CS4 can result in denial of service, application crash or arbitrary code execution. Users should apply this update since it is tagged as critical.
http://www.adobe.com/support/downloads/detail.jsp?ftpID=4291