MadsKristensen.AspNetCore.Miniblog is a blog engine built on ASP.NET Core 2.0.
Affected versions of this package are vulnerable to Remote Code Execution. Attackers can execute arbitrary code using using Data URLs within image elements. This is due to the way the
SaveFilesToDisk function in
Controllers/BlogController.cs writes a decoded base64 string to a file without validating the extension first. An attacker can abuse this function to upload malicious ASPX files and achieve remote code execution.
A fix was pushed into the
master branch but not yet published.