According to Intego, a bug in Mac OS X Leopard Quarantine feature might allows users to launch malicious attachments in Mails.
The bug causing this has to do with the way Leopard manages quarantines. The first time a user opens an attachment, Mail opens the file directly without passing through the quarantine system. Subsequent openings of the same attachment cause Mail to no longer open the attachment directly, but rather open the file it has saved in the Mail Downloads folder.
Apple should quickly react and fix the exploit.
[translation by Linathael]
