I majored in Philosophy and went directly into industry after my undergraduate. I got into programming, specifically open source, as a hobby.

I've been in industry for 7 years, and have done a few different things: DARPA-funded program analysis research, open source security engineering, running an open source engineering team, and now doing security engineering once more.

In my experience, not having a STEM degree is not a significant barrier to success (and as others have said, can be an advantage in specific contexts). My experience is that virtually nobody has cared, apart from some very funny compliance/procedural contexts where people assume that "Philosophy" means "PhD in Computer Science."