An integer overflow in NATS Server before 2.0.2 allows a remote attacker to crash the server by sending a crafted request. If authentication is enabled, then the remote attacker must have first authenticated.
https://github.com/advisories/GHSA-jp4j-47f9-2vc3
https://www.twistlock.com/labs-blog/finding-dos-vulnerability-nats-go-fuzz-cve-2019-13126/