High ISO does that, and it usually is noise, although of a different type than you're used to. The main thing to check is if it's a consistent pattern, or random? If it's consistent, it could be hot or dead pixels in different areas. Random... well, that's the hoped for option.
I've gotten the same thing shooting high iso "sliver" moon shots, where it almost looks like there are stars shining from inside the crescent, when we all really know that's impossible. High ISO in combination with exposure compensation can really make it evident.
Curious, what are your settings for this sample shot? Particularly ISO and shutter?