Vulnerability · Published Aug 6, 2025 · Assigned by microsoft
CVE-2025-53786Microsoft Exchange Server Hybrid Deployment Elevation of Privilege Vulnerability
High 8.0
In plain English
A high-severity improper authentication in Microsoft Exchange Server 2016 Cumulative Update 23 from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 7.6% (higher than 95% of all known vulnerabilities). Ready-made attack tooling exists: public proof-of-concept code.
Official description
On April 18th 2025, Microsoft announced Exchange Server Security Changes for Hybrid Deployments and accompanying non-security Hot Fix. Microsoft made these changes in the general interest of improving the security of hybrid Exchange deployments. Following further investigation, Microsoft identified specific security implications tied to the guidance and configuration steps outlined in the April announcement. Microsoft is issuing CVE-2025-53786 to document a vulnerability that is addressed by taking the steps documented with the April 18th announcement. Microsoft strongly recommends reading the information, installing the April 2025 (or later) Hot Fix and implementing the changes in your Exchange Server and hybrid environment.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft Exchange Server 2016 Cumulative Update 23 | 15.01.0.0 – before 15.01.2507.055 |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 14 | 15.02.0.0 – before 15.02.1544.025 |
| Microsoft | Microsoft Exchange Server 2019 Cumulative Update 15 | 15.02.0.0 – before 15.02.1748.024 |
| Microsoft | Microsoft Exchange Server Subscription Edition RTM | 15.02.0.0 – before 15.02.2562.017 |
Weakness: CWE-287 · Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C
References
- Microsoft Exchange Server Hybrid Deployment Elevation of Privilege Vulnerability vendor-advisory, patch