Microsoft Flags September 2026 Windows 11 Update Breaking Always On VPN

En bref

• A September 2026 Windows 11 update disrupts Always On VPN connectivity.
• Only a subset of Windows 11 machines are impacted, with no CVE assigned.
• Microsoft has issued a warning but no permanent fix yet.
• Admins should test, delay, or roll back the update as needed.

Microsoft has published a warning about a problem tied to its September 2026 security update for Windows 11. According to the company, installing this release can cause Always On VPN tunnels to fail on a portion of devices. The issue does not affect every system, but it has been confirmed on certain Windows 11 machines.

The disruption matters because Always On VPN is often used by remote and hybrid workers to reach corporate resources without manual intervention. When the tunnel drops, users lose access to file shares, internal apps, and email. For K-12 districts and government agencies, this can interrupt instruction, administration, and emergency communications.

No CVE has been assigned, which suggests this is a quality or compatibility defect rather than an exploitable vulnerability. Microsoft has not yet provided a permanent remedy, but it has acknowledged the problem. The company is likely investigating the root cause and may release an out-of-band patch or updated guidance.

Affected organizations should treat this as a medium-severity operational risk. The impact is limited to certain Windows 11 builds, but the consequences for productivity and service delivery can be significant. IT teams should verify whether their fleet uses Always On VPN and whether the September 2026 update has already been deployed.

What to watch: Microsoft's known issues dashboard, Windows release health updates, and any revised KB article. Also monitor user reports for VPN failures after patch Tuesday. If the problem spreads, Microsoft may expand the advisory or offer a scripted workaround.

À faire maintenant

1. Pause broad deployment of the September 2026 Windows 11 cumulative update on devices that rely on Always On VPN.
2. Test the update in a small pilot ring with representative VPN configurations before wider rollout.
3. If users report broken tunnels, uninstall the update or use rollback options to restore connectivity.
4. Check Microsoft's Windows release health page and known issues list for updated guidance or a fix.
5. Document affected device models and Windows builds to help Microsoft and your team isolate the cause.
6. Provide users with an alternate access method, such as a manual VPN client or web-based portal, during the outage.
7. Delay the update for critical remote workers until Microsoft confirms a permanent resolution.

Source originale

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