KB5127648 breaks WPA2-Enterprise (802.1X PEAP) Wi‑Fi authentication on Windows 11

Supply-PWC 71 Reputation points
2026-10-13T22:26:53.5766667+00:00

After installing KB5127648, Windows 11 clients can no longer authenticate to our WPA2-Enterprise (802.1X/PEAP) wireless network. Authentication starts but never completes (Event 12014: OneX Held State timeout). WPA2-Personal networks continue to work. The issue reproduces across multiple hardware vendors and wireless chipsets. Uninstalling KB5127648 immediately restores connectivity. Has anyone else observed this with PEAP-based 802.1X environments?

Windows for business | Windows Client for IT Pros | Networking | Other

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  1. Ben Green 6 Reputation points
    2026-10-15T07:31:37.75+00:00

    Microsoft have just advised in 365 Message center - Message ID MC1508562

    Take action: NTLMv1 hardening changes might affect network connections on devices without Credential Guard

    Beginning with the October 2026 security update, Windows 11, versions 26H2, 25H2, and 24H2, along with Windows Server 2025 enforce restrictions on generating NTLMv1-derived credentials for Single Sign-On by default. This planned security-hardening change is part of the boarder Microsoft effort to phase out NTLM. Microsoft originally documented the change in August 2025. This change applies only on devices with Credential Guard disabled, and might cause issues with Wi-Fi, Ethernet, and VPN connections that use MS-CHAPv2 authentication, resulting in possible failure to connect via Single Sign-On pathways...

    It links to https://support.microsoft.com/help/5066470

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