Dec 2025: Microsoft Exchange Server Elevation of Privilege Vulnerability
CVE-2025-64666 Published on December 9, 2025
Microsoft Exchange Server Elevation of Privilege Vulnerability
Improper input validation in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
Weakness Type
Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Products Associated with CVE-2025-64666
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Affected Versions
Microsoft Exchange Server 2016 Cumulative Update 23:- Version 15.01.0.0 and below 15.01.2507.063 is affected.
- Version 15.02.0.0 and below 15.02.1544.037 is affected.
- Version 15.02.0.0 and below 15.02.1748.042 is affected.
- Version 15.02.0.0 and below 15.02.2562.035 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.