A quick heads up for those of you on CS2 or CS3. FrSIRT have detailed a vulnerability in the way PNG files are handled in Photoshop and Photoshop elements. It's only a denial of service problem at the moment which makes the application crash, but it's probably best to make sure you save your work prior to opening up PNG files until Adobe issues a patch.
Sorry for the double post, but there's a bit more info on this now thanks to the team at US-CERT. It looks as if it's far worse on the Windows version of Photoshop where it could potentially be used to gain administrator access to the machine. No exploit code spotted in the wild yet though according to SANS.
