Astronomers all over are searching for extraterrestrial intelligence (SETI). While they're primarily concerned with detecting a signal and not decoding it, the detecting devices are attached to computers, making a tiny bit of risk. Andrew Siemon of SETI-Berkeley explains the small but existent danger:
"Our instruments are connected to computers, and like any computers, they can be reprogrammed," he warned. "Our software receives input that ultimately comes from unknown sources, and again, while this input is never executed or decoded, we don't perform rigorous checks to validate this unknown input like a computer security conscious programmer might do with an internet application."
Siemion speculated that, if an extraterrestrial intelligence had very deep knowledge of the software systems we use for our experiments and the architecture of our computers, they might be able to send a sequence of signals that would cause a memory buffer to overflow and perhaps allow arbitrary code execution.
Next time your game glitches up, know that it could be aliens.