ASP.NET Core Remote Code Execution Vulnerability

CVE

CVE-2026-102870

Severity

Important

CVSS base score

8.8

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Impact

Remote Code Execution

Exploitation detected

Not reported by MSRC

Publicly disclosed

No

Exploitability

Exploitation Less Likely

Component

ASP.NET Core

Weakness

CWE-94: Improper Control of Generation of Code ('Code Injection')

Issued by

Microsoft

Customer action

Required: apply the update

Affected products

.NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows, .NET 11.0 installed on Linux, .NET 11.0 installed on Mac OS, .NET 11.0 installed on Windows, Microsoft Edge (Chromium-based), Microsoft Visual Studio 2019 version 16.11, Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10, Microsoft Visual Studio 2026 version 18.11, Microsoft Visual Studio 2026 version 18.12, Microsoft.AspNetCore.Components.WebAssembly.Server, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Windows, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Windows

Updates that fix it

KB5133966: .NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows, Microsoft Edge (Chromium-based), Microsoft.AspNetCore.Components.WebAssembly.Server (restart required)

CISA KEV

Not listed in the collected catalog

EPSS

0.9%; scored 25 Oct 2026

Public exploit code

No Nuclei template listed

Published

13 Oct 2026 07:00 UTC

Last revised

25 Oct 2026 07:00 UTC

Revision note

Updated product information in the Software Update table. This is an informational change only.

• MSRC advisory
• NVD
• CVE.org
• October 2026
• KB5133966

Microsoft security releases

Complete at observationRead 25 Oct 2026 at 17:11 UTC

CISA KEV

Complete at observationRead 25 Oct 2026 at 17:11 UTC

FIRST EPSS

Complete at observationRead 25 Oct 2026 at 17:11 UTC

Public exploit code

Complete at observationRead 25 Oct 2026 at 17:11 UTC

Coverage describes the sources at this observation. A complete read then does not establish their current position.

1. 25 Oct 2026 · 17:12:51 UTC Revision noteInformation published. → Updated product information in the Software Update table. This is an informational change only.
2. 25 Oct 2026 · 17:12:51 UTC Last revised13 Oct 2026 07:00 UTC → 25 Oct 2026 07:00 UTC
3. 25 Oct 2026 · 17:12:51 UTC EPSS0.8%; scored 24 Oct 2026 → 0.9%; scored 25 Oct 2026
4. 25 Oct 2026 · 17:12:51 UTC Updates that fix itNo KB listed → KB5133966: .NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows, Microsoft Edge (Chromium-based), Microsoft.AspNetCore.Components.WebAssembly.Server (restart required)
5. 25 Oct 2026 · 17:12:51 UTC Affected productsMicrosoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Windows, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Windows → .NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows, .NET 11.0 installed on Linux, .NET 11.0 installed on Mac OS, .NET 11.0 installed on Windows, Microsoft Edge (Chromium-based), Microsoft Visual Studio 2019 version 16.11, Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10, Microsoft Visual Studio 2026 version 18.11, Microsoft Visual Studio 2026 version 18.12, Microsoft.AspNetCore.Components.WebAssembly.Server, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Windows, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Windows
6. 25 Oct 2026 · 17:12:51 UTC Link: KB5133966/windows/kb/KB5133966
7. 25 Oct 2026 · 01:34:18 UTC EPSS0.8%; scored 23 Oct 2026 → 0.8%; scored 24 Oct 2026
8. 23 Oct 2026 · 15:51:28 UTC EPSS0.8%; scored 22 Oct 2026 → 0.8%; scored 23 Oct 2026
9. 23 Oct 2026 · 09:33:49 UTC Public exploit codeUnknown: exploit-code evidence is incomplete or retained → No Nuclei template listed
10. 23 Oct 2026 · 09:33:49 UTC CISA KEVUnknown: catalog evidence is incomplete or retained → Not listed in the collected catalog
11. 23 Oct 2026 · 09:33:49 UTC Source coverage: public-exploit-codeIncomplete → Current
12. 23 Oct 2026 · 09:33:49 UTC Source coverage: first-epssIncomplete → Current

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