CVSS base score: 8.0 (High) vendor CNA · v3.1
Score assigned by the vendor's own CVE Numbering Authority (CNA); CISA's Vulnrichment program adds a score only when the CNA omits one.
Vendor: Microsoft Product: Microsoft Exchange Server 2016 Cumulative Update 23
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.
Each milestone comes from a different source, so gaps between them are gaps in what those sources publish, not evidence that nothing happened. EPSS history for this CVE holds 71 points from 2025-08-09, tracked daily from 2026-09-09; earlier points are weekly, which dates a spike to within a week. Peak probability 7.7% on 2026-09-15.
Check whether a specific version is affected →
What each source publishes about which product versions carry this vulnerability, kept as written rather than merged. Absence here means no source has published applicability data, not that nothing is affected.
No mentions found in monitored research blogs or news feeds.
Coverage across public collections only: Nuclei and OpenVAS NVT (scan);
Snort and Suricata ET Open (network); Sigma and YARA (host/SIEM);
Metasploit, Exploit-DB and public GitHub repositories (exploit). Absence
here means nothing public was found, not that detection is impossible.
GitHub PoC repositories are collected automatically by
PoC-in-GitHub (CC0) and are not vetted:
some are fakes and some are malware. Treat them as evidence that code was
published, not as code to run.
OpenVAS coverage derives from the Greenbone Community Feed, made available
under the Open Database License (ODbL) v1.0;
its individual Vulnerability Tests are licensed
GNU GPL v2.
Microsoft Exchange Server Hybrid Deployment Elevation of Privilege Vulnerability
The vendor's own judgement about their own code, shown alongside CISA's rather than merged into it. The exploitability index is a forward-looking prediction, distinct from a CVSS severity or CISA's SSVC decision, and vendors often report observed exploitation before a CVE reaches the KEV catalog. Vendor advisory →
Defensive techniques inferred by MITRE D3FEND from the underlying weakness (CWE-287) — general hardening and detection guidance for this weakness class, not a vendor patch for this specific CVE.
| Source | Date | Record |
|---|---|---|
| CISA Vulnrichment | 2025-08-06 | source record → |
| Date | Advisory | Issuer |
|---|---|---|
| 2025-08-08 | 2025-030: High Severity Vulnerability in Microsoft Exchange | CERT-EU |
| 2025-08-07 | CISA Issues ED 25-02: Mitigate Microsoft Exchange Vulnerability | CISA |
| 2025-08-06 | Microsoft Releases Guidance on High-Severity Vulnerability (CVE-2025-53786) in Hybrid Exchange Deployments | CISA |
No exploit-tool sightings recorded for this CVE.
Evidence tiers are explained on the About page — a merged Metasploit module is far stronger evidence than a distro package mention.
CVE.org record → NVD entry → Microsoft MSRC advisory → FortiGuard Labs → Rapid7 AttackerKB →