Patch tracker / KB5082417
KB5082417: .NET Framework 3.5 and 4.8.1 Security Update (April 2026)
KB5082417 is a High security update for .NET Framework 3.5 and 4.8.1, 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.
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Update summary
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.
A newer security update for Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 25H2 for ARM64-based Systems has shipped since this one: KB5120708 (2026-08-11). 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.
KB5082417 patches three CVEs in .NET 8.0 and .NET 10.0 across Linux and Mac OS runtimes, with a highest Severity of High at CVSS 7.5. The cross-platform scope matters because the exposure sits on your non-Windows .NET hosts, which are often patched on a slower cadence than Windows servers. Exploitation risk is currently low with a 2 percent EPSS and no CISA KEV listing, so this is a plan-and-schedule item rather than an emergency.
Do this: Inventory Linux and Mac OS machines running .NET 8.0 or .NET 10.0 and update their runtimes and SDKs to the KB5082417 fixed versions.
AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for KB5082417
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5082417
- 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 KB5082417 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.
| CVE | Severity | CVSS | EPSS | Exploited |
|---|---|---|---|---|
| CVE-2026-23666 | High | 7.5 | 1.3% | No |
| CVE-2026-33116 | High | 7.5 | 2.1% | No |
| CVE-2026-32226 | Medium | 5.9 | <1% | No |
Scope and sources
- Affected products
- Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 25H2 for ARM64-based Systems
- Microsoft .NET Framework 3.5 AND 4.8.1 on Windows 11 Version 25H2 for x64-based Systems
- Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2025
- Microsoft .NET Framework 3.5 AND 4.8.1 on Windows Server 2025 (Server Core installation)
- Also released in April 2026
KB5082052
114 CVEs · Critical · exploitedKB5082060
120 CVEs · Critical · exploitedKB5082063
123 CVEs · Critical · exploitedKB5082123
106 CVEs · Critical · exploitedKB5082142
115 CVEs · Critical · exploitedKB5082198
86 CVEs · Critical · exploitedKB5082200
106 CVEs · Critical · exploitedKB5083768
119 CVEs · Critical · exploitedThe full month, summarized: Microsoft Patch Tuesday.
- Authoritative references
See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.