Input validation error in Microsoft Exchange Server - CVE-2025-64666
Published: December 9, 2025
Vulnerability identifier: #VU119438
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2025-64666
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Microsoft
Affected software:
Microsoft Exchange Server
Microsoft Exchange Server
Detailed vulnerability description
The vulnerability allows a remote user to escalate privileges within the application.
The vulnerability exists due to insufficient validation of user-supplied input. A remote user can send a specially crafted request to the mail server and gain administrator privileges.
How to mitigate CVE-2025-64666
Install updates from vendor's website.