Should you update to KB5094127?
No: install KB5126657 instead. KB5094127 is a security update Microsoft released on 9 Jun 2026 for Windows PCs. It fixes 93 security flaws, 15 rated critical and 78 important by Microsoft.[1] None of them is known to be used in attacks.
It has since been replaced by KB5099539, released 14 Jul 2026, which includes all of its fixes. If you’re on an older version, install that instead.
Should you update?
No: install KB5126657 instead. KB5126657 came out on 13 Oct 2026 and includes every fix in KB5094127, so there’s no reason to stop at this one. Software Update offers the newest version your device can run.
Is KB5094127 still safe?
Not any more. The 4 updates since, up to KB5126657, fix 1,933 security flaws that KB5094127 doesn’t, and each became public the day its fix shipped. Installing it is safe: get it only from Start → Settings → Windows Update, never from a link in an email, text or pop-up.
What it fixes
Microsoft lists 93 security flaws, 15 rated critical and 78 important by Microsoft.[1] The 93 critical and important ones are:
| Flaw | Severity | What Microsoft calls it |
|---|---|---|
CVE-2025-10263 | Critical | ARM: CVE-2025-10263 Completion of affected memory accesses might not be guaranteed by completion of a TLBI [kernel] |
CVE-2026-33828 | Critical | Windows Device Health Attestation (DHA) Elevation of Privilege Vulnerability |
CVE-2026-42985 | Critical | Remote Desktop Client Remote Code Execution Vulnerability |
CVE-2026-42992 | Critical | Remote Desktop Client Remote Code Execution Vulnerability |
CVE-2026-44799 | Critical | Remote Desktop Client Remote Code Execution Vulnerability |
CVE-2026-44801 | Critical | Remote Desktop Client Remote Code Execution Vulnerability |
CVE-2026-44803 | Critical | Windows Graphics Component Remote Code Execution Vulnerability |
CVE-2026-44812 | Critical | Windows Graphics Component Remote Code Execution Vulnerability |
CVE-2026-44815 | Critical | DHCP Client Service Remote Code Execution Vulnerability |
CVE-2026-45607 | Critical | Windows Hyper-V Remote Code Execution Vulnerability |
CVE-2026-45641 | Critical | Windows Hyper-V Remote Code Execution Vulnerability |
CVE-2026-47289 | Critical | Remote Desktop Client Remote Code Execution Vulnerability |
CVE-2026-47291 | Critical | HTTP.sys Remote Code Execution Vulnerability |
CVE-2026-48563 | Critical | Remote Desktop Client Remote Code Execution Vulnerability |
CVE-2026-48574 | Critical | Windows Media Remote Code Execution Vulnerability |
CVE-2026-8863 | Important | UEFI Secure Boot Security Feature Bypass Vulnerability |
CVE-2026-34335 | Important | Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability |
CVE-2026-40404 | Important | Windows Universal Disk Format File System Driver (UDFS) Elevation of Privilege Vulnerability |
CVE-2026-40409 | Important | Windows Universal Disk Format File System Driver (UDFS) Elevation of Privilege Vulnerability |
CVE-2026-41092 | Important | Microsoft Kinect Elevation of Privilege Vulnerability |
CVE-2026-41108 | Important | Windows DNS Client Elevation of Privilege Vulnerability |
CVE-2026-42828 | Important | Windows Projected File System Elevation of Privilege Vulnerability |
CVE-2026-42836 | Important | Windows Function Discovery Service (fdwsd.dll) Elevation of Privilege Vulnerability |
CVE-2026-42837 | Important | Windows Projected File System Elevation of Privilege Vulnerability |
CVE-2026-42903 | Important | Windows Kerberos Denial of Service Vulnerability |
CVE-2026-42904 | Important | Windows TCP/IP Elevation of Privilege Vulnerability |
CVE-2026-42905 | Important | Windows DWM Core Library Elevation of Privilege Vulnerability |
CVE-2026-42906 | Important | Windows Shell Information Disclosure Vulnerability |
CVE-2026-42907 | Important | Windows Shell Information Disclosure Vulnerability |
CVE-2026-42908 | Important | Windows Remote Desktop Protocol (RDP) Information Disclosure Vulnerability |
| and 63 more | ||
How to update, and how long it takes
Usually 15 to 60 minutes in all, with one or two restarts. You can keep working while it downloads.
- Save your work first.Windows restarts to finish the update, once or twice.
- Open Start → Settings → Windows Update.Select Check for updates. Windows downloads the month’s cumulative update; it includes every earlier fix.
- Restart when it asks.Select Restart now, or schedule it for tonight. Until it restarts, the fixes aren’t in place.
- Leave automatic updates on.In the same place, under Advanced options, turn on “Get me up to date” so restarts don’t wait for days.
To check it worked: Press Windows key + R, type winver and press Enter: it shows the OS build. It should say 19045.7548 or later.
Older devices
The same day, Microsoft released KB5095051 (118 security flaws), KB5094126 (106 security flaws) and KB5093998 (102 security flaws) for devices that stay on an older version. Each fixes the same holes where they apply.
Before and after
- After: KB5099539, 14 Jul 2026, 309 security flaws
- Windows updates, every release and the latest version
- Updates, the latest version of everything HARD tracks
References
- ^ Microsoft. “KB5094127”, 9 Jun 2026.