X-aspnet-version 4.0.3: Vulnerabilities

Removing X-AspNet-Version is for .NET 4.0.3. Because the framework itself is unsupported, you must:

There have been vulnerabilities in ASP.NET that could allow for remote code execution. While specifics can vary by version and patch level, an RCE vulnerability would allow an attacker to execute arbitrary code on the server, potentially leading to full control over the server. x-aspnet-version 4.0.3 vulnerabilities

Exposing the version number is not a vulnerability per se , but it signals the presence of a known-weak platform. Below are critical vulnerabilities affecting .NET 4.0.3 (unpatched unless migrated to 4.5+). Removing X-AspNet-Version is for