See how formidable compares to other vendors in security performance
Formidable (aka node-formidable) 2.1.0 through 3.x before 3.5.3 relies on hexoid to prevent guessing of filenames for untrusted executable content; however, hexoid is documented as not "cryptographically secure." (Also, there is a scenario in which only the last two characters of a hexoid string need to be guessed, but this is not often relevant.) NOTE: this does not imply that, in a typical use case, attackers will be able to exploit any hexoid behavior to upload and execute their own content.
The User Registration WordPress plugin before 2.12 does not prevent users with at least the contributor role from rendering sensitive shortcodes, allowing them to generate, and leak, valid password reset URLs, which they can use to take over any accounts.