FAQ on Microsoft Exchange Server Hybrid Deployment Vulnerability (CVE-2025-53786)
On August 6, Microsoft published a security advisory for a vulnerability in its Microsoft Exchange Server Hybrid Deployments. CVE Description CVSSv3 CVE-2025-53786 Microsoft Exchange Server Elevation of Privilege Vulnerability (Hybrid Deployments) 8.0 The vulnerability was not exploited in the wild, but Microsoft assessed it as “Exploitation More Likely” according to its Exploitability Index. The flaw was discovered after investigating a non-security Hot Fix released on April 18. In addition to its advisory, Microsoft have issued an Emergency Directive, ED 25-02: Mitigate Microsoft Exchange Vulnerability on August 7 that requires federal agencies to take immediate action by August 11 at 9AM EST. For more information about the vulnerability, including the availability of patches and Tenable product coverage, please visit our blog.
