CF21 Hotfix13 and Fusebox applications Regarding the latest CF Hotfix (ColdFusion (2021 release) Update 13) and Fusebox5 applications. We have a legacy application in our organisation which died completely when Hotfix13 was applied. Almost every request produces a "Variable FUSEACTION is undefined." error. We have a temporary fix whereby we can set the server variable "Searchimplicitscopes" to true, but this is only a temporary solution. Has anyone else had this problem with Fusebox applications, and does anyone have a strategy for fixing it?

Yes, we saw this where the variable was unscoped. Scoping it is likely the best approach.

There is a new Adobe ColdFusion tool you could use: the new unscoped-variables-log-file, which you can generate automatically. It will detect all unscoped variables besides in your application, including, of course, those associated with Fusebox. Reference: https://helpx.adobe.com/coldfusion/kb/view-unscoped-variables-log-file.html