GHSA-f4g7-52wc-p8x7 Microsoft Security Advisory CVE-2026-96236 - ASP.NET Core Denial of Service Vulnerability

• NuGet Microsoft.AspNetCore.App.Runtime.linux-arm: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.linux-arm64: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm64: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-x64: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.linux-x64: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.osx-arm64: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.osx-x64: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.win-arm64: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.win-x64: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.win-x86: >= 8.0.0, < 8.0.32 → fixed in 8.0.32 • NuGet Microsoft.AspNetCore.App.Runtime.linux-arm: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.linux-arm64: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm64: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-x64: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.linux-x64: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.osx-arm64: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.osx-x64: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.win-arm64: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.win-x64: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.win-x86: >= 11.0.0-preview.1, < 11.0.0-rc.2 → fixed in 11.0.0-rc.2 • NuGet Microsoft.AspNetCore.App.Runtime.linux-arm: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.linux-arm64: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm64: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-x64: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.linux-x64: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.osx-arm64: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.osx-x64: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.win-arm64: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.win-x64: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.win-x86: >= 10.0.0, < 10.0.13 → fixed in 10.0.13 • NuGet Microsoft.AspNetCore.App.Runtime.linux-arm: >= 9.0.0, < 9.0.21 → fixed in 9.0.21 • NuGet Microsoft.AspNetCore.App.Runtime.linux-arm64: >= 9.0.0, < 9.0.21 → fixed in 9.0.21 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm: >= 9.0.0, < 9.0.21 → fixed in 9.0.21 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-arm64: >= 9.0.0, < 9.0.21 → fixed in 9.0.21 • NuGet Microsoft.AspNetCore.App.Runtime.linux-musl-x64: >= 9.0.0, < 9.0.21 → fixed in 9.0.21 • NuGet Microsoft.AspNetCore.App.Runtime.linux-x64: >= 9.0.0, < 9.0.21 → fixed in 9.0.21 • NuGet Microsoft.AspNetCore.App.Runtime.osx-arm64: >= 9.0.0, < 9.0.21 → fixed in 9.0.21 • NuGet Microsoft.AspNetCore.App.Runtime.osx-x64: >= 9.0.0, < 9.0.21 → fixed in 9.0.21 • NuGet Microsoft.AspNetCore.App.Runtime.win-arm64: >= 9.0.0, < 9.0.21 → fixed in 9.0.21 • NuGet Microsoft.AspNetCore.App.Runtime.win-x64: >= 9.0.0, < 9.0.21 → fixed in 9.0.21 • NuGet Microsoft.AspNetCore.App.Runtime.win-x86: >= 9.0.0, < 9.0.21 → fixed in 9.0.21

Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.Localization. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. ASP.NET Core request-localization fallback can add attacker-supplied synthetic culture names to the runtime's global cache, allowing unauthenticated requests to cause unbounded memory growth and denial of service. Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/484 CVSS Details • Version: 3.1 • Severity: High • Score: 7.5 • Vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` • Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling) Affected Platforms • Platforms: Windows, Linux, macOS • Architectures: All Affected Packages The vulnerability affects Microsoft .NET projects that use an affected package version listed below. Package name | Affected version | Patched version ------------ | ---------------- | --------------- Microsoft.AspNetCore.App.Runtime.linux-arm | >= 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 8.0.0, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 11.0.0-preview.1, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 10.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, = 9.0.0, <= 9.0.20 | 9.0.21 Microsoft.AspNetCore.App.Runtime.osx-arm64 …