Patch tracker / KB5126043
KB5126043: .NET Framework 3.5 and 4.7.2 Security Update (August 2026)
KB5126043 is a High security update for .NET Framework 3.5 and 4.7.2, released 2026-08-11. It closes 2 CVEs with a maximum CVSS of 8.8. It is the 50th largest of the 79 updates Microsoft shipped that month, by CVEs closed.
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Update summary
Fixes 2 CVEs. Most severe CVSS 8.8 (High). EPSS exploit probability up to <1%. Among the lower half of tracked Microsoft updates by EPSS exploit probability.
We checked Microsoft's support article for KB5126043 on 2026-10-11 and it lists no known issues. Read the article before broad deployment; Microsoft adds issues as reports come in, and we re-check on every refresh.
Senserva AI Opinion and rich prompt for KB5126043
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5126043
- Released
- 2026-09-08
- Last changed
- 2026-10-03
- Changes tracked
- 4
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 KB5126043 is installed
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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-2026-69522 | High | 8.8 | 3.6% | No |
| CVE-2026-62886 | High | 7.8 | 3.6% | No |
Scope and sources
- Affected products
- Microsoft .NET Framework 3.5 AND 4.6.2/4.7/4.7.1/4.7.2 on Windows Server 2019
- Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for 32-bit Systems
- Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for ARM64-based Systems
- Microsoft .NET Framework 3.5 AND 4.7.2 on Windows 10 Version 1809 for x64-based Systems
- Microsoft .NET Framework 3.5 AND 4.7.2 on Windows Server 2019
- Also released in August 2026
KB5120228
215 CVEs · Critical · exploitedKB5120229
195 CVEs · Critical · exploitedKB5120233
215 CVEs · Critical · exploitedKB5120238
183 CVEs · Critical · exploitedKB5120240
170 CVEs · Critical · exploitedKB5120242
195 CVEs · Critical · exploitedKB5120385
144 CVEs · Critical · exploitedKB5120386
139 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.