Overview

• Microsoft’s August Patch Tuesday release addresses more than 100 vulnerabilities, including CVE-2025-53786 for Exchange hybrid deployments and a publicly disclosed Windows Kerberos zero-day (CVE-2025-53779).
• CISA’s Aug. 11 Emergency Directive deadline for federal agencies to remediate the Exchange hybrid vulnerability has passed despite Shadowserver scans showing about 29,000 servers unpatched just before the cutoff.
• Microsoft and CISA report no confirmed in-the-wild exploitation of the Exchange hybrid flaw so far, but security researchers warn reliable exploit code could be developed soon.
• Microsoft advises that patching alone is insufficient and recommends deploying a dedicated hybrid app, rotating shared service principal credentials and disconnecting unsupported servers.
• Recent on-premises SharePoint attacks leveraging zero-day chains highlight the risk of post-compromise vulnerabilities enabling stealthy cloud takeovers.