Inefficient Algorithmic Complexity in Microsoft products - CVE-2026-118749

Vulnerability identifier: #VU165191

CSH Severity: Medium

CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-118749

CWE-ID: CWE-407

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to inefficient algorithmic complexity in ASP.NET Core when processing network requests. A remote attacker can send specially crafted requests that trigger excessive computational resource consumption to cause a denial of service.

.NET
Microsoft.Extensions.Validation
Visual Studio
Ubuntu
aspnetcore-runtime-10.0 (Ubuntu package)
dotnet-runtime-10.0 (Ubuntu package)
dotnet-hostfxr-10.0 (Ubuntu package)
dotnet-host-10.0 (Ubuntu package)
dotnet10 (Ubuntu package)
dotnet-sdk-aot-10.0 (Ubuntu package)
dotnet-sdk-10.0 (Ubuntu package)
aspnetcore-runtime-11.0 (Ubuntu package)
dotnet-host-11.0 (Ubuntu package)
dotnet-hostfxr-11.0 (Ubuntu package)
dotnet-runtime-11.0 (Ubuntu package)
dotnet-sdk-11.0 (Ubuntu package)
dotnet-sdk-aot-11.0 (Ubuntu package)
dotnet11 (Ubuntu package)

Install security update from vendor's website.

.NET - update to 11.0.0
Microsoft.Extensions.Validation - update to 11.0.0
Visual Studio - update to 18.12.0
aspnetcore-runtime-10.0 (Ubuntu package) - update to 10.0.15-0ubuntu1~26.10.1
dotnet-runtime-10.0 (Ubuntu package) - update to 10.0.15-0ubuntu1~26.10.1
dotnet-hostfxr-10.0 (Ubuntu package) - update to 10.0.15-0ubuntu1~26.10.1
dotnet-host-10.0 (Ubuntu package) - update to 10.0.15-0ubuntu1~26.10.1
dotnet10 (Ubuntu package) - update to 10.0.115-10.0.15-0ubuntu1~26.10.1
dotnet-sdk-aot-10.0 (Ubuntu package) - update to 10.0.115-0ubuntu1~26.10.1
dotnet-sdk-10.0 (Ubuntu package) - update to 10.0.115-0ubuntu1~26.10.1
aspnetcore-runtime-11.0 (Ubuntu package) - update to 11.0.0-0ubuntu1~26.10.1
dotnet-host-11.0 (Ubuntu package) - update to 11.0.0-0ubuntu1~26.10.1
dotnet-hostfxr-11.0 (Ubuntu package) - update to 11.0.0-0ubuntu1~26.10.1
dotnet-runtime-11.0 (Ubuntu package) - update to 11.0.0-0ubuntu1~26.10.1
dotnet-sdk-11.0 (Ubuntu package) - update to 11.0.100-0ubuntu1~26.10.1
dotnet-sdk-aot-11.0 (Ubuntu package) - update to 11.0.100-0ubuntu1~26.10.1
dotnet11 (Ubuntu package) - update to 11.0.100-11.0.0-0ubuntu1~26.10.1

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-118749
• https://learn.microsoft.com/en-us/visualstudio/releases/2026/release-notes

• Multiple vulnerabilities in .NET
• Ubuntu update for dotnet10, dotnet11, dotnet8