From the looks of it, Linkin Park should be set to play Festival Rock One in Portimão, Portugal on August 5th. The festival is four days long, stretching from August 5th to August 8th and will be held at the Algarve International Motor Park. The source for this can be found here.
Nothing is totally confirmed yet as far as we know, so DO NOT buy tickets until the show has officially been announced on LP.com. We'll let you know as soon as that happens if it does.