CVE-2021-31186: Windows Remote Desktop Protocol (RDP) Information Disclosure Vulnerability

Severity: medium (CVSS 4.3 v2.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 3.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-05-11 · updated 2026-06-17

Description

Windows Remote Desktop Protocol (RDP) Information Disclosure Vulnerability

Affected products

Microsoft Windows 10 Version 1607: 20h2, 1607, 1803, 1809, 1909, 2004
Microsoft Windows 7: all versions
Microsoft Windows 8.1: all versions
Microsoft Windows RT 8.1: all versions
Microsoft Windows Server 2008: r2-sp1
Microsoft Windows Server 2012: r2
Microsoft Windows Server 2016: 20h2, 1909, 2004
Microsoft Windows Server 2019: all versions
Microsoft Windows 10 Version 1507: from 10.0.0 before 10.0.10240.18931 — fixed in 10.0.10240.18931
Microsoft Windows 10 1607: from 10.0.0 before 10.0.14393.4401 — fixed in 10.0.14393.4401
Microsoft Windows 10 1803: from 10.0.0 before 10.0.17134.2207 — fixed in 10.0.17134.2207
Microsoft Windows 10: from 10.0.0 before 10.0.17763.1935 — fixed in 10.0.17763.1935
Microsoft Windows 10 1909: from 10.0.0 before 10.0.18363.1556 — fixed in 10.0.18363.1556
Microsoft Windows 10 2004: from 10.0.0 before 10.0.19041.982 — fixed in 10.0.19041.982
Microsoft Windows 10 20H2: from 10.0.0 before 10.0.19042.982 — fixed in 10.0.19042.982
Microsoft Windows 7: from 6.1.0 before 6.1.7601.24597; from 6.1.0 before 6.1.7601.24598 — fixed in 6.1.7601.24597, 6.1.7601.24598
Microsoft Windows 7 Service Pack 1: from 6.1.0 before 6.1.7601.24597; from 6.1.0 before 6.1.7601.24598 — fixed in 6.1.7601.24597, 6.1.7601.24598
Microsoft Windows 8.1: from 6.3.0 before 6.3.9600.20017 — fixed in 6.3.9600.20017
Microsoft Windows Server 2008 R2 Service Pack 1: from 6.1.0 before 6.1.7601.24597; from 6.1.0 before 6.1.7601.24598 — fixed in 6.1.7601.24597, 6.1.7601.24598
Microsoft Windows Server 2008 Service Pack 2: from 6.0.0 before 6.0.6003.21117 — fixed in 6.0.6003.21117
Microsoft Windows Server 2012: from 6.2.0 before 6.2.9200.23347 — fixed in 6.2.9200.23347
Microsoft Windows Server 2012 R2: from 6.3.0 before 6.3.9600.20017 — fixed in 6.3.9600.20017
Microsoft Windows Server 2016: from 10.0.0 before 10.0.14393.4401 — fixed in 10.0.14393.4401
Microsoft Windows Server 2019: from 10.0.0 before 10.0.17763.1935 — fixed in 10.0.17763.1935
Microsoft Windows Server, version 1909 (Server Core installation): from 10.0.0 before 10.0.18363.1556 — fixed in 10.0.18363.1556
Microsoft Windows Server version 2004: from 10.0.0 before 10.0.19041.982 — fixed in 10.0.19041.982
Microsoft Windows Server version 20H2: from 10.0.0 before 10.0.19042.982 — fixed in 10.0.19042.982

How to fix

Upgrade to a fixed version: Microsoft Windows 10 Version 1507 10.0.10240.18931; Microsoft Windows 10 1607 10.0.14393.4401; Microsoft Windows 10 1803 10.0.17134.2207; Microsoft Windows 10 10.0.17763.1935; Microsoft Windows 10 1909 10.0.18363.1556; Microsoft Windows 10 2004 10.0.19041.982; Microsoft Windows 10 20H2 10.0.19042.982; Microsoft Windows 7 6.1.7601.24597, 6.1.7601.24598; Microsoft Windows 7 Service Pack 1 6.1.7601.24597, 6.1.7601.24598; Microsoft Windows 8.1 6.3.9600.20017; Microsoft Windows Server 2008 R2 Service Pack 1 6.1.7601.24597, 6.1.7601.24598; Microsoft Windows Server 2008 Service Pack 2 6.0.6003.21117. Check the vendor advisory for mitigations.

References

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