The OASIS and Mitre Corporation Staff are developing an open source TAXII 2.0 Server to support the global cyber threat intelligence community in its build-out of the STIX 2.0 ecosystem. The taxii-server code under development is in a GitHub repository. It is a Python library which will process HTTPS requests from TAXII clients in conformance with the TAXII specification. Contributions to this OASIS Open Repository are invited from all parties, whether affiliated with OASIS or not. Participants must have a GitHub account, but no fees or OASIS membership obligations are required.
You can access the code at:
https://github.com/oasis-open/cti-taxii-server
It is currently being maintained by Rich Piazza and Greg Back of the Mitre Corporation. They encourage feedback through the use of issues or comments directly on the GitHub site.