Medium 5.5Known exploited (CISA KEV)Published Jun 8, 2021

CVE-2021-31955Windows Kernel Information Disclosure Vulnerability

Updated under an hour ago (Oct 27, 2026, 10:30 AM ET)

Does this affect you?

It affects Microsoft Windows 10 Version 1809 and 7 other products. Add what you run to find out whether that includes you.

CISA lists it as known exploited since Nov 3, 2021; federal agencies had to remediate by Nov 17, 2021. Treat that date as your deadline.

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Every CVE for Microsoft Windows 10 Version 1809

Exploited in the last 30 days

Windows Kernel Information Disclosure Vulnerability

CVSS: 5.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:F/RL:O/RC:C
Weakness (CWE): CWE-497
Known exploited: Added to CISA KEV Nov 3, 2021; federal remediation due Nov 17, 2021Apply updates per vendor instructions.
EPSS (exploitation in the next 30 days): 81.11% (percentile 100)
Assigned by: microsoft
NVD analysis: Analyzed
Record last updated: Oct 21, 2025
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

Microsoft Windows 10 Version 1809 microsoft:windows_10_1809	from 10.0.0 before 10.0.17763.1999	CNA record
Microsoft Windows Server 2019 microsoft:windows_server_2019	from 10.0.0 before 10.0.17763.1999	CNA record
Microsoft Windows 10 Version 1909 microsoft:windows_10_1909	from 10.0.0 before 10.0.18363.1621	CNA record
Microsoft Windows 10 Version 21H1 microsoft:windows_10_21h1	from 10.0.0 before 10.0.19043.1052	CNA record
Microsoft Windows Server version 2004 microsoft:windows_server_2004	from 10.0.0 before 10.0.19041.1052	CNA record
Microsoft Windows 10 Version 20H2 microsoft:windows_10_20h2	from 10.0.0 before 10.0.19042.1052	CNA record
Microsoft Windows Server version 20H2 microsoft:windows_server_20h2	from 10.0.0 before 10.0.19042.1052	CNA record
microsoft windows_10_1809 microsoft:windows_10_1809	before 10.0.17763.1999	NVD
microsoft windows_10_1909 microsoft:windows_10_1909	before 10.0.18363.1621	NVD
microsoft windows_10_2004 microsoft:windows_10_2004	before 10.0.19041.1052	NVD
1–10 of 15

References

References

https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31955	x-refsource-misc, patch, vendor-advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-31955	us-government-resource

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.