Microsoft Exchange Server
CVE-2025-64666 — Microsoft Exchange Server Elevation of Privilege Vulnerability
Executive Summary
Improper input validation in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
Overview
7.5
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
CVSS Vector
ATTACK VECTOR
Network
ATTACK COMPLEXITY
High
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
Temporal Score: 6.5
EPSS Score
0.00983
probability of exploitation in the next 30 days
0.57697 percentile - updated 2026-06-20
View on FIRST.org
Affected Products
4 affected products
| Product | KB Article | Severity | Impact | Restart Required |
|---|---|---|---|---|
| Microsoft Exchange Server 2016 Cumulative Update 23 | 5071873 (Security Update) |
Important | Elevation of Privilege | Yes |
| Microsoft Exchange Server 2019 Cumulative Update 14 | 5071874 (Security Update) |
Important | Elevation of Privilege | Yes |
| Microsoft Exchange Server 2019 Cumulative Update 15 | 5071875 (Security Update) |
Important | Elevation of Privilege | Yes |
| Microsoft Exchange Server Subscription Edition RTM | 5071876 (Security Update) |
Important | Elevation of Privilege | Yes |
Patches
4 patches
| Article | Type | Restart |
|---|---|---|
5071873 |
Security Update | Yes |
5071874 |
Security Update | Yes |
5071875 |
Security Update | Yes |
5071876 |
Security Update | Yes |
Known Exploits
No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.
Acknowledgments
National Security Agency
References
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