CVE-2025-64666
Microsoft Exchange Server Elevation of Privilege Vulnerability
Improper input validation in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
Microsoft Exchange Server Elevation of Privilege Vulnerability
Improper input validation in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
- Record
CVE-2025-64666- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - Weakness
- CWE-20
- Updated
- 2026-11-02
EUVDEUVD-2025-202236
Improper input validation in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
- Record
EUVD-2025-202236- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-mr7p-99h9-v459
Improper input validation in Microsoft Exchange Server allows an authorized attacker to elevate...
Improper input validation in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
- Record
GHSA-mr7p-99h9-v459- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
NVD
Improper input validation in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
- Record
CVE-2025-64666- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-20
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-64666 is a high vulnerability (CVSS 7.5) in Microsoft Exchange Server, published December 9, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.02%, the 63rd percentile. No source names a fixed version.