The py_sha3_new_impl function in sha3module.c has error handling code that looks like this:

    error:
      if (self) {
          Py_DECREF(self);
      }
      if (data && buf.obj) {
          PyBuffer_Release(&buf);
      }

However, there is a `goto error` before the variable buf is initialized. If that error path is triggered, the function will attempt to free an invalid object, possibly leading to a program crash.