How to fix ASP.NET Core Vulnerability HTTP request smuggling bug scores 9.9

ASP.NET Core HTTP request smuggling bug scores 9.9

‘Highest Ever’ Severity Score Assigned by Microsoft to ASP.NET Core Vulnerability

Microsoft fixes highest-severity ASP.NET Core flaw ever (bleepingcomputer.com)

CVE-2025-55315 is an HTTP request smuggling bug leading to information leaks, file content tampering, and server crashes.

What is HTTP request smuggling

How to fix the issue 

Microsoft Security Advisory CVE-2025-55315: .NET Security Feature Bypass Vulnerability · Issue #371 · dotnet/announcements (github.com)