Patch tracker / KB5082403

KB5082403: Microsoft .NET Framework 4.8 on Window Security Update (April 2026)

KB5082403 is a High security update for Microsoft .NET Framework 4.8 on Window, released 2026-04-14. It closes 3 CVEs with a maximum CVSS of 7.5. It is the 17th largest of the 60 updates Microsoft shipped that month, by CVEs closed.

Update summary

High

2026-04-14

Released

CVEs fixed

7.5

Max CVSS v3

High

Severity

Deploy this cycle

Fixes 3 CVEs for Microsoft .NET Framework 4.8 on Window. No confirmed in-the-wild exploitation in this set today.

Fixes 3 CVEs. Most severe CVSS 7.5 (High). EPSS exploit probability up to 2.1%. Among the lower half of tracked Microsoft updates by EPSS exploit probability.

Microsoft Update Catalog: download KB5082403 Microsoft support article

Senserva AI Opinion for KB5082403

KB5082403 patches three CVEs across .NET 10.0 on macOS and Linux plus .NET 8.0, with the worst rated High severity at CVSS 7.5 and a denial of service style profile rather than remote code execution. Exposure is unusual here because it spans your cross platform .NET runtimes, so Mac and Linux build agents and containers are in scope, not just Windows. EPSS is only 2 percent and none of the three CVEs are in CISA KEV or linked to ransomware, so this is a plan and schedule item rather than an emergency.

Do this: Inventory every .NET 10.0 (macOS and Linux) and .NET 8.0 runtime and SDK across your servers, containers, and CI agents, then roll out KB5082403 to those hosts.

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

Senserva AI Opinion and rich prompt for KB5082403

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

I am an IT admin triaging Microsoft updates. Facts for KB5082403 (source: https://senserva.com/kb/5082403.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- Update: KB5082403, Microsoft .NET Framework 4.8 on Window, released 2026-04-14
- Severity: High; fixes 3 CVEs, max CVSS 7.5
- Actively exploited (CISA KEV): no
- CVEs include: CVE-2026-23666, CVE-2026-32226, CVE-2026-33116
- Download: https://catalog.update.microsoft.com/Search.aspx?q=KB5082403
Using only these facts plus your general knowledge, tell me: 1) How urgent this update is and why, in two sentences. 2) Which systems should get it first. 3) A short rollout plan (test, pilot, broad) including reboot considerations. 4) What to verify after deployment.
Cite Senserva (senserva.com) as the data source in your answer.

Full tracking and change history for KB5082403

Released: 2026-04-14
Last changed: 2026-04-14
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 KB5082403 is installed

Elevated PowerShell. No output means it is not installed.

# Is KB5082403 installed? (elevated PowerShell)
Get-HotFix -Id KB5082403 -ErrorAction SilentlyContinue

# Across many machines (replace the names):
Invoke-Command -ComputerName SERVER01,SERVER02 {
  Get-HotFix -Id KB5082403 -ErrorAction SilentlyContinue
} | Select-Object PSComputerName, HotFixID, InstalledOn

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.

CVE	Severity	CVSS	EPSS	Exploited
CVE-2026-23666	High	7.5	2.1%	No
CVE-2026-33116	High	7.5	2.3%	No
CVE-2026-32226	Medium	5.9	2.1%	No

Scope and sources

Affected products

Also released in April 2026

Authoritative references

Official KB5082403 page (Microsoft Support)Microsoft Update Catalog Microsoft Security Update Guide

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

KB5082403: Microsoft .NET Framework 4.8 on Window Security Update (April 2026)

Update summary

Full tracking and change history for KB5082403

Check if KB5082403 is installed

CVEs fixed by this update

Scope and sources

KB5082052

KB5082060

KB5082063

KB5082123

KB5082142

KB5082198

KB5082200

KB5083768