MC1486397
Prevent or fix issuesMajor changeAdmin impact
An updated version of the September 2026 Scan Cab is available
Microsoft 365 Message Center Archive by Merill Fernando · Microsoft may not have sent this notice to your tenant.Microsoft asks admins to prevent or fix an issue. Read what it asks below and check the linked documentation; whether your tenant is affected is not known here.
What the notice says
Microsoft’s text, with source markup removedIMPORTANT: This notice is only relevant for environments where: Exchange Server Subscription Edition (SE) is used Scan Cab is used to check for update compliance The September 2026 Scan Cab was deployed before 6:30 PM PDT on October 2, 2026. What and why: An updated version of the September 2026 Scan Cab was made available at 6:30 PM PDT on October 2, 2026. This Scan Cab includes new metadata corresponding to new updates for Exchange Server. The new Microsoft update for Exchange Server released October 2, 2026, included additional protections to address CVE-2026-96940: Exchange Server Elevation of Privilege Vulnerability. See the additional information section of this message for details. Rollout schedule: The updated September 2026 Scan Cab was made available at 6:30 PM PDT on October 2, 2026. Who is affected: IT administrators who downloaded the Scan Cab before 6:30 PM PDT on October 2, 2026, should re-acquire and re-deploy it if the Scan Cab is used to assess updates for environments where Exchange Server is used. No action is required on environments where Scan Cab is not employed and do not have Exchange Server. However, please note that there might be non-Microsoft applications that utilize Scan Cab. Review the documentation for any software and update deployment tools that might be in use for your organization, to understand if this is applicable in your environment. What will happen: Administrators can re-deploy the updated Scan Cab via their usual processes. For detailed guidance, see the Additional information section below. Additional information: Updated Scan Cab: Download the new Scan Cab here CVE-2026-96940 - Microsoft Exchange Server Elevation of Privilege Vulnerability Exchange Team Blog: September 2026 V2 Exchange Server Security Updates KB5129955: Security update for Microsoft Exchange Server Subscription Edition Announcing a smaller WSUS Scan Cab - Microsoft Tech Community: Learn more about WSUS and the Scan Cab process Using WUA to Scan for Updates Offline - Win32 apps: Windows Update Agent (WUA) can be used to scan computers for security updates without connecting to Windows Update WSUS and the Catalog Site: The Catalog Site used by WSUS to import updates and drivers
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-96940
- https://catalog.s.download.windowsupdate.com/microsoftupdate/v6/wsusscan/wsusscn2.cab
- https://techcommunity.microsoft.com/blog/exchange/released-september-2026-v2-exchange-server-security-updates/4561718
- https://support.microsoft.com/servicing/exchange/server/update/2026/5129955
- https://techcommunity.microsoft.com/blog/windows-itpro-blog/announcing-a-smaller-wsus-scan-cab/3980495
- https://learn.microsoft.com/windows/win32/wua_sdk/using-wua-to-scan-for-updates-offline
- https://learn.microsoft.com/windows-server/administration/windows-server-update-services/manage/wsus-and-the-catalog-site
What changed
Between archive captures, newest firstThe archive supplies one version of this notice.
Linked documentation
Microsoft pages the notice links toRelated public evidence
- Public source · 13 Oct 2026MC1506286: Notice: The October 2026 Scan Cab for Microsoft updates is delayed Microsoft 365 Message Center Archive by Merill FernandoShared reference: https://techcommunity.microsoft.com/blog/windows-itpro-blog/announcing-a-smaller-wsus-scan-cab/3980495
- Public source · 14 Sep 2026MC1471885: An updated version of the September 2026 Scan Cab is available Microsoft 365 Message Center Archive by Merill FernandoShared reference: https://techcommunity.microsoft.com/blog/windows-itpro-blog/announcing-a-smaller-wsus-scan-cab/3980495
- Public source · 8 Sep 2026MC1469328: Notice: The September 2026 Scan Cab for Microsoft updates is delayed Microsoft 365 Message Center Archive by Merill FernandoShared reference: https://techcommunity.microsoft.com/blog/windows-itpro-blog/announcing-a-smaller-wsus-scan-cab/3980495
Not confirmed here
What this page cannot tell you- Whether your tenant is affected: this is Microsoft's notice, not a check of your settings.
- 2 linked pages have not been read yet.