https://www.planetary.org/the-downlink/shortchanging-nasa-is-simply-not-smart

A hardy fungus may challenge planetary protection efforts. A recent study has identified a fungus called Aspergillus calidoustus living in NASA cleanrooms even after decontamination. This species could potentially survive the radiation, near-vacuum, and temperature conditions of deep space, meaning it could be carried on spacecraft to Mars or other worlds.