Patch tracker / KB5097149

KB5097149: .NET 8.0 installed on Windows Security Update (June 2026)

KB5097149 is a High security update for .NET 8.0 installed on Windows, released 2026-06-09. It closes 3 CVEs with a maximum CVSS of 7.8. It is the 13th largest of the 18 updates Microsoft shipped that month, by CVEs closed.

Update summary

High
2026-06-09
Released
3
CVEs fixed
7.8
Max CVSS
High
Severity
Deploy this cycle
Fixes 3 CVEs for .NET 8.0 installed on Windows. No confirmed in-the-wild exploitation in this set today.

Fixes 3 CVEs. Most severe CVSS 7.8 (High). EPSS exploit probability up to 2.4%. Among the top half of tracked Microsoft updates by EPSS exploit probability.

Senserva found thiswe track every release for this product line, so we can tell you this package is behind

A newer security update for .NET 10.0 installed on Windows has shipped since this one: KB5100984 (2026-07-14). For cumulative update families the newer package includes these fixes, so installing that one is usually the shorter path. Verify against your own update rings before you skip this package.

Microsoft Update Catalog: download KB5097149Microsoft support article
Senserva AI Opinion for KB5097149

KB5097149 patches three vulnerabilities across .NET 8.0, 9.0, and 10.0 runtimes installed on Windows, with the worst rated High severity at CVSS 7.8. Any server or workstation running applications built on these three .NET versions is exposed, which in practice covers a broad slice of both self-hosted apps and installed tooling. EPSS remains low at 2 percent and none of the CVEs are in CISA KEV or linked to ransomware, so this is a scheduled fix rather than a fire drill.

Do this: Inventory hosts running .NET 8.0, 9.0, or 10.0 and apply KB5097149 through your normal update ring for those runtimes.

AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for KB5097149

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

Full tracking and change history for KB5097149

Released
2026-06-09
Last changed
2026-06-09
Changes tracked
1

Senserva began recording day-to-day change history on 2026-07-07, and refreshes it several times a day. Release dates are historical where Microsoft publishes them; revision history is tracked from that date forward, so it does not include changes made before then.

Check if KB5097149 is installed

Elevated PowerShell. No output means it is not installed.

CVEs fixed by this update

Sorted exploited-first, then by CVSS. Every CVE links to its Senserva page with the full risk facts, references, and a ready-to-paste AI prompt.

CVESeverityCVSSEPSSExploited
CVE-2026-45490High7.82.4%No
CVE-2026-45591High7.52.4%No
CVE-2026-45491Medium6.22.4%No

Scope and sources

Affected products
Also released in June 2026

KB5087423

66 CVEs · Critical

KB5087539

66 CVEs · Critical

KB5089466

61 CVEs · Critical

KB5089549

61 CVEs · Critical

KB5093998

158 CVEs · Critical

KB5094126

107 CVEs · Critical

KB5094128

105 CVEs · Critical

KB5002876

8 CVEs · High

The full month, summarized: Microsoft Patch Tuesday.

Authoritative references
Official KB5097149 page (Microsoft Support)Microsoft Update CatalogMicrosoft Security Update Guide

See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.

New to a term on this page? CVE, KB, KEV, CVSS, and EPSS are each explained once, on the Senserva security lexicon. Reference: Microsoft CVE and vulnerability management and the Microsoft patching guide.
Provided as is, without warranty; verify against the vendor advisory before acting. Data notice and terms.