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Fencer Vulns
high 7.5

CVE-2025-64666 json

Microsoft Exchange Server Elevation of Privilege Vulnerability

published 2025-12-09 10 mo ago modified 2026-10-14 25 d ago also EUVD-2025-202236

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.0%
EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits
0
none known

Summary

Improper input validation in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.

Patch / fix

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 23 15.01.2507.063
  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 14 15.02.1544.037
  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 15 15.02.1748.042
  • Microsoft Microsoft Exchange Server Subscription Edition RTM 15.02.2562.035

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
10 mo ago

Exploit prediction

1.02% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 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
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Microsoft Microsoft Exchange Server 2016 Cumulative Update 23
  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 14
  • Microsoft Microsoft Exchange Server 2019 Cumulative Update 15
  • Microsoft Microsoft Exchange Server Subscription Edition RTM

Classification

Weakness
  • CWE-20 Improper Input Validation
Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.