Improper input validation in Microsoft Exchange Server
CVE-2025-64666
Improper input validation in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.010 (63.1th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 63rd percentile — 63.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000
Affected products
- Microsoft Exchange Server — versions 2016, 2019
- Microsoft Exchange Server Subscription Edition
- Microsoft Exchange Server 2016 Cumulative Update 23 — versions 15.01.0.0
- Microsoft Exchange Server 2019 Cumulative Update 14 — versions 15.02.0.0
- Microsoft Exchange Server 2019 Cumulative Update 15 — versions 15.02.0.0
- Microsoft Exchange Server Subscription Edition Rtm — versions 15.02.0.0
Weakness classification (CWE)
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2025-64666 (vendor-advisory, patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2025-64666?
- CVE-2025-64666 is a high-severity vulnerability in Microsoft Exchange Server, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2025-12-09.
- How severe is CVE-2025-64666?
- High severity. CVSS v3 base score is 7.5 out of 10.