SB2026011386 - Multiple vulnerabilities in Microsoft Tablet Windows User Interface (TWINUI) Subsystem

Description

This security bulletin contains information about 2 vulnerabilities.

1) Race condition (CVE-ID: CVE-2026-20826)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a race condition in Tablet Windows User Interface (TWINUI) Subsystem. A local user can exploit the race and escalate privileges on the system.

2) Information disclosure (CVE-ID: CVE-2026-20827)

CWE-ID: CWE-200 - Exposure of sensitive information to an unauthorized actor

CVSSv4: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear

The vulnerability allows a local user to gain access to potentially sensitive information.

The vulnerability exists due to excessive data output by the application in Tablet Windows User Interface (TWINUI) Subsystem. A local user can gain unauthorized access to sensitive information on the system.

Remediation

Install update from vendor's website.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20826
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20827