Personalize WebPage - Access Denied CU 16.0.19725.20522 KB 5002893

The trace shows that the patched ToolPane now checks Add and Customize Pages, whose permission mask is 0x40000. Because that permission allows classic-page changes, granting it to ordinary contributors is unsafe. First confirm the August cumulative update is installed on every SharePoint server, reboot where required, and complete the build-to-build upgrade with the SharePoint Products Configuration Wizard or PSConfig on every server. Verify the farm reports no upgrade-required servers or databases. Reproduce the issue on a clean classic Web Part page with an unchanged built-in permission level, then capture the ULS correlation ID and compare behavior before and after the CU in a nonproduction farm. If the clean reproduction persists, treat it as a CU regression and open a Microsoft support case referencing KB 5002893, build 16.0.19725.20522, the permission mask, and ULS trace. Avoid editing web.config, replacing binaries, or broadly adding 0x40000 while awaiting an official fix.