Starting from NiFi 1.14, you can specify the TLS ciphers to be used by NiFi web service by using below property:
nifi.web.https.ciphersuites.include
You can also specify the TLS Ciphers to be excluded by using below property:
nifi.web.https.ciphersuites.exclude
This enhancement is part of Apache Jira NIFI-3580.
For Cloudera CFM, these properties are exposed (and usable) from CFM 2.1.3 and above.
Note: The values for above properties should take the form of a comma-separated list of common cipher names as specified here. The regular expressions (for example ^.*GCM_SHA256$) may also be specified.