Kudos to Outdustry.com for breaking out the story: basically, it looks like Chinese crackers are now able to generate iTunes vouchers redeemable on the iTunes Music Store.
Unsurprisingly, these vouchers are sold online in China (look for yourself). In case you're wondering how long it will take for these to show up on Ebay, here's the answer.
How's that for a security leak? Very, very bad.