[dalu]

Yesterday I needed a regex fuzzer but couldn't find any (except some Windows SDL whatever that means, I'm not developing on Windows) In the end I just created a very limited whitelist of input characters allowed and didn't use a "security tool"

[0xad]

You can use grammarinator or any other of myriad grammar fuzzers BUT I'd start with radamsa and its string-related flags. Radamsa is _awesome_, you run it on an input and you get mutated output. Works both for binary files and text fles (such as grammars).