CloudBleed is an ongoing bug affecting websites using CloudFlare , a company offering internet security, a content delivery system, and DNS services. This bug randomly returns private messages, credentials, and other pieces of data to the user on certain requests.
With up to 1.2 Million Leaks Bad , Cloudflare Released a statement on Feb. 23, 2017 acknowledging the leaks may have started as early as Sept. 22, 2016 but stated they have found no evidence of malicious exploitation.
People using affected services should change their passwords to protect against the possibility of their credentials being returned and out on the web.
Some major websites affected:
- OK Cupid
And to learn more about this here are some places to start..