"There has been a major security flaw within Cloudflare and thus meaning within Discord. Its highly suggested that you cycle your passwords everywhere.

Impact:
Between 2016-09-22 - 2017-02-18 passwords, private messages, API keys, and other sensitive data were leaked by Cloudflare to random requesters.
Data was cached by search engines, and may have been collected by random adversaries over the past few months.

"The greatest period of impact was from February 13 and February 18 with around 1 in every 3,300,000 HTTP requests through Cloudflare potentially resulting in memory leakage (that’s about 0.00003% of requests), potential of 100k-200k paged with private data leaked every day"

What you should do:
Change all your passwords, especially those on these affected sites. Rotate API keys & secrets, and confirm you have 2-FA set up for important accounts. Of the sites compromised, most notably there is Reddit, Uber, StackOverflow, Patreon, DigitalOcean, 4chan, and many many more.

You can check which sites were affected by this on the readme of this github page https://github.com/pirate/sites-using-cloudflare"