Bug fix retracted for Windows 11 Always On VPN

Microsoft initially announced that a bug affecting Always On VPN configurations in Windows 11 was fixed, but later admitted the issue was not fully resolved. The problem has been causing disruptions for professional users since September, making it difficult for some to connect to company networks remotely.

Remote work affected by unresolved issue

Certain Always On VPN configurations have been struggling to establish or re-establish connections to company networks, sometimes cutting off employees from essential remote resources. Microsoft had believed the issue was resolved with security updates released on October 13, but it later acknowledged that the fix had not worked.

Microsoft removes incorrect fix from updates

On October 20, Microsoft updated the version notes for two security updates, KB5127648 and KB5127646, to remove the previously announced bug fix. The fix remains unresolved, and the issue is still under investigation. The automatic selection of connection protocols is a key point of concern.

Technical details of the bug

The bug specifically affects Always On VPN configurations that automatically choose a connection protocol or attempt to switch protocols if the first one fails. For example, a connection might switch from IKEv2 to SSTP but then get stuck in a loop, showing repeated connection attempts or error messages like "The specified port is already in use."

Microsoft updates incident status and apologizes

In a message to IT administrators, Microsoft updated the status of the incident to "mitigated" and apologized for having prematurely announced the resolution. The communication, referenced as WI1482218 and reported by The Register, urged affected companies to continue using the recommended workaround: disabling automatic protocol selection and enforcing a single protocol.

Microsoft plans future fix but urges caution

Microsoft has once again promised to release a proper fix in the coming weeks, though it has not provided an exact timeline. In the meantime, users are advised not to uninstall the October updates, which address other critical bugs and were part of a Patch Tuesday update that fixed over 1,400 security vulnerabilities.