Is Workplace vulnerable to the “Cloudbleed” security bug?
No, you can rest assured your data is safe!
Cloudbleed is isolated to the CloudFlare service. Workplace does not use CloudFlare (or any “accelerator” or caching servers).
You can find out more about Cloudbleed here: https://en.wikipedia.org/wiki/Cloudbleed
For more information about the security of your data refer to Data security