CVE-2025-21225Network attack vector

Gateway service interruption via type confusion

Published Jan 14, 2025 · Updated Jun 9, 2026

Type confusion in RD Gateway on Microsoft Windows Server allows remote attackers to interrupt the gateway service over a network. Microsoft identifies incompatible-type resource access in RD Gateway but has not disclosed the affected function, object, or packet field. The attack requires no privileges or user interaction, but exploitation has high complexity and affects availability only.

CVSS severity5.9
Medium
EPSS probability1.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Type confusion in RD Gateway on Microsoft Windows Server allows remote attackers to interrupt the gateway service over a network. Microsoft identifies incompatible-type resource access in RD Gateway but has not disclosed the affected function, object, or packet field. The attack requires no privileges or user interaction, but exploitation has high complexity and affects availability only.

The record

CVE
CVE-2025-21225
Published
Jan 14, 2025
Updated
Jun 9, 2026
Vendor
Microsoft
Product
Windows Server 2019
Classifications
CWE-843, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.17763.0 <10.0.17763.6775

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Windows Server 2019version=10.0.17763.0 <10.0.17763.6775
Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.2894
Microsoft · Windows Server 2016 (Server Core installation)version=10.0.14393.0 <10.0.14393.7699
Microsoft · Windows Server 2022, 23H2 Edition (Server Core installation)version=10.0.25398.0 <10.0.25398.1369
Microsoft · Windows Server 2016version=10.0.14393.0 <10.0.14393.7699
Microsoft · Windows Server 2019 (Server Core installation)version=10.0.17763.0 <10.0.17763.6775
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.3091
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.2894

Published CVSS scores

5.9MicrosoftCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-843Access of Resource Using Incompatible Type ('Type Confusion')
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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