Within Umbraco Forms, configuring a malicious URL on the Webservice data source can result in Remote Code Execution. This affects all Umbraco Forms versions running on .NET Framework (up to and including version 8).
The 'Send email' workflow does not HTML encode the user-provided field values in the sent email message, making any form with this workflow configured vulnerable, as it allows sending the message from a trusted system and address (potentially bypassing spam and email client security systems).
Character limits configured by editors for short and long answer fields are validated only client-side, not server-side.
This affects all versions of package UmbracoForms. When using the default configuration for upload forms, it is possible to upload arbitrary file types. The package offers a way for users to mitigate the issue. The users of this package can create a custom workflow and frontend validation that blocks certain file types, depending on their security needs and policies.