madskristensen Miniblog.Core through 2019-01-16 allows remote attackers to execute arbitrary ASPX code via an IMG element with a data: URL, because SaveFilesToDisk in Controllers/BlogController.cs writes a decoded base64 string to a file without validating the extension.
https://rastating.github.io/miniblog-remote-code-execution/
https://github.com/madskristensen/Miniblog.Core/blob/master/src/Controllers/BlogController.cs#L142