Windows 11 KB5127648 Reportedly Breaks WPA-2 Enterprise 802.1x PEAP Wi-Fi Authentication, But This Registry Fix May Help

Windows 11 October 2026 Patch Tuesady update, KB5127648, is reportedly causing serious headaches for some business networks. The latest Patch Tuesday update, which appears to have fixed previously reported the Group Policy failure, has apparently broken WPA2-Enterprise Wi-Fi and wired 802.1X authentication.

Windows 11 KB5127648 reportedly breaks enterprise authentication

The user reports, first spotted by Neowin, suggests that the issue affects enterprise environments using 802.1X authentication with PEAP. According to affected users, WPA2-Personal connections continue working, while enterprise Wi-Fi and Ethernet authentication fail. A few adminis revealed thar uninstalling KB5127648 immediately restored Wi-Fi connectivity. While, some reported success after changing a Windows registry setting.

Interestingly, Microsoft’s official release notes do not currently list this authentication failure among KB5127648’s known issues. In case you are unaware, Microsoft made some changes to NTLMv1-derived credentials last year, which can affect single sign-on for MS-CHAPv2-based Wi-Fi, Ethernet, and VPN connections.

Here’s the registry workaround reported by users

The workaround involves setting BlockNtlmv1SSO to 0, which keeps the feature in Audit mode instead of blocking NTLMv1-derived credentials. Microsoft documents this setting and explains that 1 enables enforcement. Some affected administrators report that changing it to 0 restored authentication.

To try it, open Registry Editor as an administrator and navigate to:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\MSV1_0

Then, Find or create a DWORD (32-bit) Value named BlockNtlmv1SSO. Next, Set its value to 0, then restart the device and test authentication. Finally, back up the registry first, and consult your IT administrator before applying this change across managed devices.