AMD has confirmed reports that Steam codes for copies of Dirt 3 offered as part of a promotion with publisher Codemasters have been accessed and distributed online.
It said in a statement that it intends to honour all valid game vouchers, but that the current situation "may result in a short delay".
"This past weekend, activation keys associated with free Dirt 3 game vouchers shipping with select AMD products were compromised," the graphics card maker said.
"These activation keys were hosted on a third party fulfilment agency website, www.AMD4u.com, and did not reside on AMD's website. Neither the AMD nor Codemasters servers were involved.
"We are working closely with Steam, Codemasters, and our fulfilment agency to address the situation," it added. "AMD will continue to honour all valid game vouchers, however the current situation may result in a short delay before the vouchers can be redeemed."