Today i found a valid cnpj not passing @CNPJ validation constraint. After digging a little, i realized that all valid cnpj with check digit 0 were failing. Looking at the source of CNPJValidator i found an issue with the configuration of the Mod11CheckValidator, in the initialization an 'X' was supplied as treatCheck10As parameter.
But a valid cnpj doesn't contains 'X' character, in this case a '0' was expected. (the same as CPFValidator).
I've tested against hibernate validator 5.2.0.CR1 and 5.2.0.Alpha1, and both versions were failing.
I've also created a pull request with the test case i found the bug.