Patch tracker / KB5120240
KB5120240: Windows 11 Version 23H2 Security Update (August 2026)
KB5120240 is a Critical security update for Windows 11 Version 23H2, released 2026-08-11. It closes 160 CVEs with a maximum CVSS of 9.8. At least one of them is actively exploited (CISA KEV), so this is a deploy-first update. The most likely of them to be attacked is CVE-2026-68820, which FIRST.org rates at 9% probability of exploitation in the next 30 days.
Our data comes from Microsoft, CISA and other public sources, and it can be wrong or out of date. If you are unsure, check the linked source before you act, and tell us when we are wrong so we can fix it.
Update summary
Fixes 160 CVEs. At least one is actively exploited (CISA KEV). Most severe CVSS 9.8 (Critical). EPSS exploit probability up to 8.6%. Among the top half of tracked Microsoft updates by EPSS exploit probability.
A newer security update for Windows 11 Version 23H2 for ARM64-based Systems has shipped since this one: KB5126653 (2026-10-13). 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.
We checked Microsoft's support article for KB5120240 on 2026-10-29 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 KB5120240
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for KB5120240
- Released
- 2026-08-11
- Last changed
- 2026-10-30
- Changes tracked
- 14
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.
- 2026-08-23 CVEs fixed 170 to 171
Recorded by Senserva on the dates shown, from the MSRC release feed. This is what moved and when, which neither the vendor advisory nor NVD publishes.
Check if KB5120240 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.
Scope and sources
- Affected products
- Also released in August 2026
KB5120228
204 CVEs · Critical · exploitedKB5120229
184 CVEs · Critical · exploitedKB5120233
204 CVEs · Critical · exploitedKB5120238
174 CVEs · Critical · exploitedKB5120242
184 CVEs · Critical · exploitedKB5120385
136 CVEs · Critical · exploitedKB5120386
131 CVEs · Critical · exploitedKB5120418
162 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.