https://community.extremenetworks.com/t5/extremecontrol/windows-kb5127648-breaking-802-1x-authentication/m-p/122818#M2221 <P>Hello Team,</P><P>Just to help others: if you started seeing 802.1X authentication problems (Wi‑Fi or Ethernet) after the October Patch Tuesday, check if the affected devices have KB5127648 installed. There are many reports of issues with PEAP‑MSCHAPv2, and in many cases removing the update restores connectivity.</P><P>This looks like another step from Microsoft to move away from older technologies based on NTLMv1/MS‑CHAPv2. There is a workaround by changing the Windows registry (BlockNtlmv1SSO=0), but in the long term it probably makes more sense to move to EAP‑TLS instead of continuing to rely on PEAP‑MSCHAPv2.</P><P><A href="https://learn.microsoft.com/en-us/answers/questions/6036507/kb5127648-breaks-wpa2-enterprise-802-1x-peap-wi-fi?page=2#answers" target="_blank">https://learn.microsoft.com/en-us/answers/questions/6036507/kb5127648-breaks-wpa2-enterprise-802-1x-peap-wi-fi?page=2#answers</A></P><P>I hope this is helpful to someone.</P> Thu, 15 Oct 2026 11:01:19 GMT dariusmp 2026-10-15T11:01:19Z https://community.extremenetworks.com/t5/extremecontrol/windows-kb5127648-breaking-802-1x-authentication/m-p/122818#M2221 <P>Hello Team,</P><P>Just to help others: if you started seeing 802.1X authentication problems (Wi‑Fi or Ethernet) after the October Patch Tuesday, check if the affected devices have KB5127648 installed. There are many reports of issues with PEAP‑MSCHAPv2, and in many cases removing the update restores connectivity.</P><P>This looks like another step from Microsoft to move away from older technologies based on NTLMv1/MS‑CHAPv2. There is a workaround by changing the Windows registry (BlockNtlmv1SSO=0), but in the long term it probably makes more sense to move to EAP‑TLS instead of continuing to rely on PEAP‑MSCHAPv2.</P><P><A href="https://learn.microsoft.com/en-us/answers/questions/6036507/kb5127648-breaks-wpa2-enterprise-802-1x-peap-wi-fi?page=2#answers" target="_blank">https://learn.microsoft.com/en-us/answers/questions/6036507/kb5127648-breaks-wpa2-enterprise-802-1x-peap-wi-fi?page=2#answers</A></P><P>I hope this is helpful to someone.</P> Thu, 15 Oct 2026 11:01:19 GMT https://community.extremenetworks.com/t5/extremecontrol/windows-kb5127648-breaking-802-1x-authentication/m-p/122818#M2221 dariusmp 2026-10-15T11:01:19Z