Inconsistent interpretation of HTTP requests in ASP.NET Core and Visual Studio - CVE-2025-55315

Vulnerability identifier: #VU117236

CSH Severity: Medium

CVSS v4: 6.4 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:L]

CVE-ID: CVE-2025-55315

CWE-ID: CWE-444

Exploitation vector: Remote access

Exploit availability: Public exploit is available

The vulnerability allows a remote attacker to perform HTTP request smuggling attacks.

The vulnerability exists due to improper validation of HTTP requests in ASP.NET. A remote user can send a specially crafted HTTP request to the server and smuggle arbitrary HTTP headers.

Successful exploitation of vulnerability may allow an attacker to poison HTTP cache and perform phishing attacks.

ASP.NET Core
Visual Studio
Tenable Identity Exposure (formerly Tenable.ad)
Red Hat OpenShift Dev Spaces
Red Hat Enterprise Linux for x86_64
Red Hat CodeReady Linux Builder for IBM z Systems
Red Hat CodeReady Linux Builder for ARM 64
Red Hat CodeReady Linux Builder for Power, little endian
Red Hat CodeReady Linux Builder for x86_64
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Ubuntu
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
dotnet10 (Ubuntu package)
dotnet8.0 (Red Hat package)
dotnet9.0 (Red Hat package)

Install updates from vendor's website.

ASP.NET Core - addressed in versions 8.0.21 8.0.21, 9.0.10 9.0.10
Visual Studio - addressed in versions 17.10.20 17.10.20, 17.12.13 17.12.13
Tenable Identity Exposure (formerly Tenable.ad) - addressed in versions 3.77.14, 3.93.4
Red Hat OpenShift Dev Spaces - update to 3.25.0
dotnet10 (Ubuntu package) - addressed in versions 8.0.21-0ubuntu1~22.04.1, 8.0.21-0ubuntu1~24.04.1, 8.0.21-0ubuntu1~25.04.1, 8.0.21-0ubuntu1~25.10.1, 8.0.121-0ubuntu1~22.04.1, 8.0.121-0ubuntu1~24.04.1, 8.0.121-0ubuntu1~25.04.1, 8.0.121-0ubuntu1~25.10.1, 8.0.121-8.0.21-0ubuntu1~22.04.1, 8.0.121-8.0.21-0ubuntu1~24.04.1, 8.0.121-8.0.21-0ubuntu1~25.04.1, 8.0.121-8.0.21-0ubuntu1~25.10.1, 9.0.10-0ubuntu1~25.04.1, 9.0.10-0ubuntu1~25.10.1, 9.0.111-0ubuntu1~25.04.1, 9.0.111-0ubuntu1~25.10.1, 9.0.111-9.0.10-0ubuntu1~25.04.1, 9.0.111-9.0.10-0ubuntu1~25.10.1, 10.0.0~rc2-0ubuntu1~25.10.2, 10.0.100~rc2-0ubuntu1~25.10.2, 10.0.100-10.0.0~rc2-0ubuntu1~25.10.2
dotnet8.0 (Red Hat package) - addressed in versions 8.0.121-1.el8_10, 8.0.121-1.el9_4, 8.0.121-1.el9_6, 8.0.121-1.el10_0
dotnet9.0 (Red Hat package) - addressed in versions 9.0.111-1.el8_10, 9.0.111-1.el9_6, 9.0.111-1.el10_0

• Exploit #12105 - CVE-2025-55315-PoC-Exploit (November 14, 2025)
• Exploit #12034 - CVE-2025-55315- (October 24, 2025)
• Exploit #12033 - CVE-2025-55315-detection-playground (October 24, 2025)

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2025-55315

• Inconsistent interpretation of HTTP requests in Microsoft ASP.NET
• Red Hat Enterprise Linux 8 update for .NET 8.0
• Red Hat Enterprise Linux 9 update for .NET 8.0
• Red Hat Enterprise Linux 9 update for .NET 8.0
• Ubuntu update for dotnet10
• Tenable Identity Exposure update for third-party components
• Red Hat Enterprise Linux 10 update for .NET 8.0
• Red Hat Enterprise Linux 10 update for .NET 9.0
• Red Hat Enterprise Linux 8 update for .NET 9.0
• Red Hat Enterprise Linux 9 update for .NET 9.0
• Tenable Identity Exposure 3.77 update for third-party components
• Multiple vulnerabilities in Red Hat OpenShift Dev Spaces