CVE-2026-20838 — Windows Kernel Information Disclosure Vulnerability

Executive Summary

Generation of error message containing sensitive information in Windows Kernel allows an authorized attacker to disclose information locally.

Overview

5.5

CVSS MEDIUM

Important

MS Severity

Not Exploited

MS Exploit Status

Less Likely

MS Exploit Likelihood

Category Information Disclosure

Released Jan 13 2026

Last Updated Jan 13 2026

Publicly Disclosed No

CISA KEV Not Listed

Known Exploits None Known

EPSS Score 0.00633 — 0.45541 percentile

NVD CVSS 5.5 MEDIUM — matches MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C

ATTACK VECTOR

Local

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

None

AVAILABILITY

None

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 4.8

EPSS Score

0.00633

probability of exploitation in the next 30 days

0.45541 percentile - updated 2026-06-21

View on FIRST.org

Affected Products

11 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 11 Version 23H2 for ARM64-based Systems	`5073455 (Security Update)`	Important	Information Disclosure	Yes
Windows 11 Version 23H2 for x64-based Systems	`5073455 (Security Update)`	Important	Information Disclosure	Yes
Windows 11 Version 24H2 for ARM64-based Systems	`5074109 (Security Update)`	Important	Information Disclosure	Yes
Windows 11 Version 24H2 for x64-based Systems	`5074109 (Security Update)`	Important	Information Disclosure	Yes
Windows 11 Version 25H2 for ARM64-based Systems	`5074109 (Security Update)`	Important	Information Disclosure	Yes
Windows 11 Version 25H2 for x64-based Systems	`5074109 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2022	`5073457 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2022 (Server Core installation)	`5073457 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2022, 23H2 Edition (Server Core installation)	`5073450 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2025	`5073379 (Security Update)`	Important	Information Disclosure	Yes
Windows Server 2025 (Server Core installation)	`5073379 (Security Update)`	Important	Information Disclosure	Yes

Patches

5 patches

Article	Type	Restart
`5073455`	Security Update	Yes
`5074109`	Security Update	Yes
`5073457`	Security Update	Yes
`5073450`	Security Update	Yes
`5073379`	Security Update	Yes

Known Exploits

No known exploits have been linked for this CVE yet. When available, exploit references will be sourced from public repositories and may be unverified, incomplete, or non-functional. Always review code carefully before use in any environment.

Acknowledgments

Microsoft Offensive Research & Security Engineering

References

MSRC Advisory MITRE NVD