PatchTheCVEWindows 11 26H1: security updates (KB) and vulnerabilities
2 KB updates fix 6 tracked CVEs for Windows 11 26H1.
Windows 11 26H1 has 6 tracked vulnerabilities, 0 critical. A fixed release or vendor patch exists for 6. Most recent: 2026-10-13. Highest priority: CVE-2026-96960 (score 52/100).
- CVE-2026-96960 HIGH 7.5 UPGRADE DOWNGRADE Asymmetric resource consumption (amplification) in .NET allows an unauthorized attacker to deny service over a
- CVE-2026-96959 HIGH 7.5 UPGRADE DOWNGRADE Allocation of resources without limits or throttling in .NET allows an unauthorized attacker to deny service o
- CVE-2026-62772 HIGH 7.8 UPGRADE Heap-based buffer overflow in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized
- CVE-2026-62799 HIGH 7.8 UPGRADE Heap-based buffer overflow in Windows SMB Client allows an authorized attacker to elevate privileges locally.
- CVE-2026-72971 MEDIUM 5.5 UPGRADE Improper link resolution before file access ('link following') in Windows Container Isolation FS Filter Driver
- CVE-2026-62775 MEDIUM 5.5 UPGRADE Incorrect authorization in Windows Container Isolation FS Filter Driver (unionfs.sys) allows an authorized att
FAQ
How do I fix Windows 11 26H1 vulnerabilities?
Open the CVE for your version, check the affected range, then follow the listed action: upgrade to the fixed release, or downgrade or mitigate if no fix exists yet. Commands for each OS are shown on every CVE page.
Is Windows 11 26H1 being exploited right now?
None of the tracked Windows 11 26H1 CVEs are on the CISA Known Exploited Vulnerabilities list at the moment. This is checked every 20 minutes.
Which Windows 11 26H1 CVE should I patch first?
CVE-2026-96960 currently ranks highest (52/100): Asymmetric resource consumption (amplification) in .NET allows an unauthorized attacker to deny service over a.
Security updates (KB) for Windows 11 26H1
| KB | Fixed build | CVEs fixed | Newest CVE |
|---|---|---|---|
| KB5127696 | 2.0.50727.9188 AND 3.0.30729.9171 | 2 | 2026-10-13 |
| KB5121000 | 10.0.28000.2704 | 4 | 2026-08-11 |
Install the KB from Windows Update, then verify with Get-HotFix -Id KBxxxxxxx or winver. Fixed build is the OS build number after the update.