# KB5133966: October 2026 security update

KB5133966, released October 25, 2026, fixes 4 CVEs across 6 products. One of them is being exploited (CVE-2026-111497); 1 on CISA KEV. Patch Radar priority: Patch now.

- Web page: https://patchblox.com/security/fix/microsoft/kb5133966
- Platform: Microsoft
- Released: Oct 25, 2026
- Priority: Patch now (Closes CVE-2026-111497, exploited (CISA KEV))
- CVEs: 4, exploited: 1, on CISA KEV: 1
- Vendor advisory: https://support.microsoft.com/help/5133966

## Applies to

| Product | Release | Fixed in |
|---|---|---|
| [.NET 10.0 installed on Linux](https://patchblox.com/security/data/product/microsoft/net-10.0-installed-on-linux.md) |  |  |
| [.NET 10.0 installed on Mac OS](https://patchblox.com/security/data/product/microsoft/net-10.0-installed-on-mac-os.md) |  |  |
| [.NET 10.0 installed on Windows](https://patchblox.com/security/data/product/microsoft/net-10.0-installed-on-windows.md) |  |  |
| [.NET source-build Linux tarballs (all archive types)](https://patchblox.com/security/data/product/microsoft/net-source-build-linux-tarballs-all-archive-types.md) |  |  |
| [Microsoft.AspNetCore.Components.WebAssembly.DevServer](https://patchblox.com/security/data/product/microsoft/microsoft.aspnetcore.components.webassembly.devserver.md) |  |  |
| [Microsoft.AspNetCore.Components.WebAssembly.Server](https://patchblox.com/security/data/product/microsoft/microsoft.aspnetcore.components.webassembly.server.md) |  |  |

## CVEs this fix closes

| CVE | Priority | Component | CVSS | EPSS | Exploitation |
|---|---|---|---:|---:|---|
| [CVE-2026-111497](https://patchblox.com/security/data/cve/CVE-2026-111497.md) | Patch now | .NET | 9.8 | 0.8264 | CISA KEV, Disclosed |
| [CVE-2026-102870](https://patchblox.com/security/data/cve/CVE-2026-102870.md) | High | ASP.NET Core | 9.4 | 0.0091 |  |
| [CVE-2026-70197](https://patchblox.com/security/data/cve/CVE-2026-70197.md) | High | .NET | 8.1 | 0.0079 |  |
| [CVE-2026-114148](https://patchblox.com/security/data/cve/CVE-2026-114148.md) | High | ASP.NET Core | 8.1 | 0.0036 |  |

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Data as of 2026-11-07T06:34:28Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo