RSA Security Analytics does not support CIDR when the MetaCallback option is selected. Ranged indices are still required for feeds that only need ip.src or ip.dst, but not both.
In 10.6.5, support is provided for MetaCallback feeds for CIDR on Decoder and Log Decoder devices using the existing custom feed advanced configuration wizard. To access the wizard, go to Live > Feeds, > Custom Feed > Advanced Configuration Wizard, and use the xml feed definition file.
You can also upload xml and feed binary files using the REST interface with /decoder/parsers/upload.