Other folks have mentioned that optimizing compilers are more aggressive these days. To that I'd add: - More applications are talking to the internet and being

Other folks have mentioned that optimizing compilers are more aggressive these days. To that I'd add: - More applications are talking to the internet and being exposed to malicious input. There's also more money to be made in finding exploits, and more people and governments looking. At the same time, fuzzing techniques are getting dramatically better. - Applications are more likely to run across different architectures (mobile) and different compiler versions (faster pace of compiler development), leading to more opportunities for "something weird" to happen. Multithreading is also more common. - Memory-safe languages have taken a larger market share, and the popular attitude towards memory safety issues is changing from "bugs are a fact of life" to "this is a drawback of specific languages".