CVSS Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Short block sizes makes the webserver vulnerable to hit the same hash for multiple inputs. By observing the data for a longer period of time, an attacker can recover secure HTTP cookies.
To prevent SWEET32, make sure that you only use cipher suites with large block sizes. Refer to Secure TLS Configuration for more information on how to configure good cipher suites.